Question
A can complete a piece of work in 10 days. B in 15 days
and C in 20 days. A and C worked together for two days and then A was replaced by B. In how many days, altogether, was the work completed (in days)?Solution
Work done by ( A + C ) in 2 days = 2 (1/10 + 1/20 ) = 2 ((2 + 1)/20 ) = 6/20 = 3/10 Remaining work = 1 - 3/10 = 7/10 ( B + C )’s 1 day’s work = 1/15 + 1/20 = (4 + 3)/60 = 7/60 Time taken by ( B + C ) to finish 7/10 part of the work = 60/7 × 7/10 = 6 days Total time = 2 + 6 = 8 days Alternate method: Let total work = LCM (10,15,20) = 60 units So A’s 1 day work = 60/10 = 6 units B’s 1 day work = 60/15 = 4 units C’s 1 day work = 60/20 = 3 units A & C’s work for 2 days = (6+3)×2 = 18 units So remaining work = 60 – 18 = 42 units Now A is replaced by B So B & C together will do work in 1 day = 3 + 4 = 7 units So they can do the remaining job in = 42/ 7 = 6 days So total days = 6 + 2 = 8 days
What approximate value should replace the question mark?
12.45% of 640.20 − 60% of 2500 = ? − 9000.10
`[(7.99)^2 - (13.001)^2 + (4.01)^3]^2=` ?
- What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)
What value should come in place of question mark (?) in the following question. (You need not to calcualte the exact value)
?/647 = 226/ ?
- What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)
A, B & C have Rs.1550 together. If they divide the money in the ratio 1:3:1 respectively. Find the difference of amount received by B and C.
What approximate value should come in the place of (?) in the following questions?
∛(92.8 + √1025) * ? = 16.06% of 750
√1024.21 × √624.89 ÷ 4.98 + 11.99 × 4.01 = ?
√784 × 3 + (713.99 ÷ 6.98) = ?% of 619.99
11.11% of (123.45 + 234.56) + 10.01³ - (5.05 of 7.07) = ? of (88.88 - 33.33)
