Question 1:  If the cost of $40$ toys is $1024$ Rs. what is the cost of one dozen such toys?

Cost of $40$ toys $= 1024$ Rs.

Therefore cost of $1$ toy $= (1024/40) = 25.60$ Rs.

Hence the cost of one dozen toys ( $12$ toys) $= 25.60 \times 12 = 307.20$ Rs.

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Question 2: If $18$ notebooks cost $333$ Rs. how many notebooks can be purchased for $425.50$ Rs?

Cost of $18$ notebooks $= 333$ Rs

Cost of one notebook $= (33/18) = 18.5$ Rs.

Hence number of notebooks that can be purchased for $425.50$ Rs $= (425.50/18.5) = 23$

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Question 3: If $50$ pencils can be bought for $120$ Rs. how many pencils can be bought for $108$ Rs.?

$50$ pencils cost $= 120$ Rs.

Cost of one pencil $= (120/50) = 2.4$ Rs.

Hence the number of pencils that can be bought for $108$ Rs. $= (108/2.4) = 45$ pencils

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Question 4: If $45$ iron rods of the same size weigh $12.6$ kg, how much is the weight of $24$ such rods?

Weight of $45$ rods $= 12.6$ kg

Weight of one rod $= (12.6/45) = 0.28$ kg

Weight of $24$ such rods $= 0.28 \times 24 = 6.72$ kg

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Question 5: If a laborer earns $784$ Rs. per week, how much will he earn in $15$ days?

Weekly salary of the labor $= (784 /7) = 112$ Rs.

Earning for $15$ days $= 15 \times 1$

Daily Salary of the labor $= 15 \times 112 = 1680$ Rs

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Question 6: If a car covers $56.7$ km in $4.5$ liters of petrol, how many kilometres will it cover in $26$ liters of petrol?

In $4.5$ liters of petrol the car covers $= 56.7$ km

In one liter of petrol the car will cover $= (56.7/4.5) = 12.6$ km

In $26$ liters of petrol, the car will cover $= 12.6 \times 26 = 327.6$ km

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Question 7: $15$ men can do a piece of work in $36$ hours. How many men will be required to finish the work in $20$ hours?

$15$men can do a piece of work in $36$ hours

Total man hours required for finishing the job $= 15 \times 36 = 540$ man hours

To finish the work in $20$ hours we would need $=540/20 = 27$ men

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Question 8: $13$ men can weave $117$ baskets in a week. How many men will be needed to weave $189$ baskets in $3$ days?

$117$ baskets are produced in $= 13 \times 7 = 91$ man days

To produce one basket $= (117/91) = 9/7$ man days

The no. of men required to produce $189$ baskets in $3$ days $= (7 \times 189)/ (3 \times 9) = 49$ men

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Question 9: A journey by car takes $48$ minutes at $65$ km/hr. How fast must the car go to finish the journey in $40$ minutes?

Distance covered by the car in $48$ minutes $= 65 \times (48/60) = 52$ km

Speed at which the car must go to finish the journey in $40$ minutes $= (52 \times 60/40) = 78$ km/hr.

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Question 10: In a zoo, $28$ parrots consume $7420$ g of nuts in a day. If $8$ parrots are sent to another zoo, what quantity of nuts will be required in a day?

$28$ parrots consume $= 7420$ gm of nuts

$1$ parrot will consume $= (7420/28) = 265$ gm of nuts

Hence $20$ parrots will consume $= 265 \times 20 = 5300$ g of nuts per day

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Question 11: If $5$ men or $7$ women can earn $700$ Rs. per day, how much would $7$ men and $11$ women earn per day?

$5$ men earn $= 700$ Rs. Per day

Hence, $1$ man would earn $= (700/5) = 140$ Rs. Per day

Similarly, $1$ woman would earn $= (700/7) = 100$ Rs. Per day

Therefore $7$ men and $11$ women would earn $= 7 \times 140 + 11 \times 100 = 2080$ Rs. Per day.

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Question 12: If $5$ laborers earn $9000$ in $15$ days, how many laborers can earn $6720$ in $8$ days?

$5$ laborers in $15$ days earn $= 9000$ Rs.

$75$ labor days $= 9000$ Rs.

$1$ Labor Day $= (9000/75) = 120$ Rs. Per day

Hence the number of laborers days required to earn $6720$ Rs in $8$ days = $(6720/120) = 56$

Therefore the number of laborer required $= 56/8 = 7$ laborers

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Question 13:. A fort had provisions for $450$ men for $80$ days. After $10$ days, $50$ more men arrived. How long will the remaining food last at the same rate?

Provision $= 450 \times 80 = 36000$ man days

Food consumed by $450$ men in $10$ day $= 450 \times 10 = 4500$ man days

Provisions left $= 36000 - 4500 = 31500$ man days

After $10$ days, the number of men $= 450 + 50 = 500$

Therefore the number of days the provision would last $= 31500/500 = 63$ days

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Question 14: $3$ typists working $7$ hours a day, type a thesis in $10$ days. For how many hours per day should $2$ typists work to finish it in $21$ days?

Total work to be done $= 3 \times 7 \times 10 = 210$ man hours

So the number of hours per day by for $2$ typists in $21$ days $= (210/42) = 5$ hours per day

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Question 15: $7$ workers working $6$ hours a day can build a wall in $12$ days. How many days will $3$ workers take to build a similar wall, working $8$ hours a day?

Total man hours to build a wall $= 7 \times 6 \times 12 = 504$ man hours
Number of days $3$ workers working $8$ hours a day to complete the wall $= 504/(3 \times 8) = 21$ days