Two typists of varying skills can do a typing job in 6 minutes if they work together. If the first typist typed alone for 4 minutes and then the second typist typed alone for 6 minutes, they would be left with 1/5 of the whole work. How many minutes would it take the slower typist, to complete the typing job working alone?
Two typists of varying skills can do a typing job in 6 minutes if they work together. If the first typist typed alone for 4 minutes and then the second typist typed alone for 6 minutes, they would be left with 1/5 of the whole work. How many minutes would it take the slower typist, to complete the typing job working alone? Correct Answer 15 minutes
Given:
If both typist work together, then they complete the work in = 6 min
Formula:
Total work = Efficiency × Time
Calculation:
Let efficiency of first and second typist be x and y respectively, then
⇒ Total work = (x + y) × 6 ----(1)
If 1/5 of work left, then done work = 1 – 1/5 = 4/5
According second condition
Total work × 4/5 = (4x + 6y)
⇒ Total work = (4x + 6y) × 5/4 ----(2)
From equation (1) and equation (2)
(x + y) × 6 = (4x + 6y) × 5/4
⇒ 24x + 24y = 20x + 30y
⇒ 24x – 20x = 30y – 24y
⇒ 4x = 6y
⇒ x/y = 6/4
⇒ x : y = 3 : 2
Total work = (3 + 2) × 6 = 30 unit
∴ Slower typist can complete the work in = 30/2 = 15 minutes