Question
A is 60% as efficient as B, and C is 50% as efficient as
A. If A, B, and C working together can finish a task in 15 days, how many days will it take for B to complete the same task on his own?Solution
Let B’s efficiency be 1 unit/day. Then, A’s efficiency = 0.6 units/day and C’s efficiency = 0.5 × 0.6 = 0.3 units/day. Combined efficiency of A, B, and C = 0.6 + 1 + 0.3 = 1.9 units/day. They can complete the work in 15 days, so total work = 1.9 × 15 = 28.5 units. Time taken by B to complete the work alone = Total work ÷ B’s efficiency = 28.5 ÷ 1 = 28.5 days. Final Answer: (c) 28.5 days
What will come in the place of [?] in the following equation if '÷' and ' X ' are interchanged?
20 - 6 ÷ 15 X 5 + 9 - 8 = ?
In an imaginary mathematical system, symbol '–' stands for addition, symbol '+' stands for division, symbol '×' stands for subtraction, and symbol '�...
If 34 – 28 means 952, 544 + 8 means 68, 20 ÷ 5 means 25, 20 x 10 means 10, then 375 – 11 x 270 ÷ 550 + 11 x 35 = ?
Select the correct combination of mathematical signs that can sequentially replace the “@” sign and balance the following equation.
14@6@8@3@...
Which of the following interchange of sign would make the given equation correct?
45 × 9 + 5 ÷ 4 = 25
If '+' means 'division', '-' means 'multiplication', '÷' means 'addition' and ' X ' means 'subtraction', then what is the value of the following expres...
If '+' means ' - ', ' X ' means '+', ' - ' means '÷' and '÷' means ' X ', then what is the value of the following expression?
32 ÷ 8 X 117 - 1...
By interchanging which two signs the question will be correct?
15 + 5 ÷ 2 – 9 × 3 = 22
If,
40 – 14 means 560,
168 + 8 means 21,
26 ÷ 2 means 28,
8 x 7 means 1,
then 410 – 7 x 290 ÷ 350 + 7 x 21 = ?
4 – 10 × 5 + 9 ÷ 3 = 51
