Chain Rule Practice Questions

5 questions per page • Detailed step-by-step solutions

Question 16
Hard
A contract is to be completed in 46 days and 117 men were set to work, each working 8 hours a day. After 33 days, 4/7 of the work is completed. How many additional men may be employed so that the work may be completed in time, each man now working 9 hours a day?
A 75 men
B 81 men
C 90 men
D 96 men
Correct Answer: B

Explanation:

Remaining days = 46 - 33 = 13 days. Remaining work = 3/7. (117 * 33 * 8) / (4/7) = (M2 * 13 * 9) / (3/7) => (117 * 33 * 8) / 4 = (M2 * 13 * 9) / 3 => 7722 = 39 * M2 => M2 = 198 men. Additional men needed = 198 - 117 = 81 men.
Question 17
Easy
21 binders can bind 1400 books in 15 days. How many binders will be required to bind 800 books in 20 days?
A 7 binders
B 9 binders
C 10 binders
D 12 binders
Correct Answer: B

Explanation:

Using (M1 * D1) / W1 = (M2 * D2) / W2: (21 * 15) / 1400 = (M2 * 20) / 800 => 315 / 1400 = M2 / 40 => M2 = (315 * 40) / 1400 = 9 binders.
Question 18
Easy
If a quarter kg of potato costs 60 paise, how many paise will 200 gm cost?
A 42 paise
B 45 paise
C 48 paise
D 50 paise
Correct Answer: C

Explanation:

Quarter kg = 250 gm. Cost of 250 gm = 60 paise. Cost of 1 gm = 60 / 250 paise. Cost of 200 gm = 200 * (60 / 250) = 48 paise.
Question 19
Easy
There is sufficient food for 40 men for a 15 days picnic. If after 6 days 4 men leave, how many more days can the remaining men intake food?
A 9 days
B 10 days
C 11 days
D 12 days
Correct Answer: B

Explanation:

After 6 days, remaining food lasts 40 men for (15 - 6) = 9 days. Remaining men = 40 - 4 = 36 men. 40 * 9 = 36 * D2 => D2 = 360 / 36 = 10 days.
Question 20
Medium
If 8 men can reap 80 hectares in 24 days, then how many hectares can 36 men reap in 30 days?
A 400 hectares
B 450 hectares
C 480 hectares
D 500 hectares
Correct Answer: B

Explanation:

Using (M1 * D1) / W1 = (M2 * D2) / W2: (8 * 24) / 80 = (36 * 30) / W2 => 192 / 80 = 1080 / W2 => 2.4 = 1080 / W2 => W2 = 1080 / 2.4 = 450 hectares.