Question

A takes 10 days less than B to complete a work, and together they do it in 12 days. In how

many days can B alone do the work?​

Answer 1

Answer:

30 days

Step-by-step explanation:

Let's B alone take x days to finish the work.

B’s 1 days work = 1/x

A alone can finish the work in = x - 10

A’s 1 days work= 1/(x-10)

Given: A and B together can finish the same work in 12 days.

(A and B)'s 1 days work = 1/12

A’s 1 days work + B’s 1 days work = 1/x + 1/(x-10)

ATQ

1/x + 1/(x-10) = 1/12

(x-10) + x / x(x-10) = 1/12

x-10 + x / x² -10x = 1/12

2x -10 / x² -10x = 1/12

12(2x -10) = x² -10x

24x -120 = x² -10x

x² -10x -24x +120= 0

x² -34x +120= 0

x² 30x -4x +120= 0

x( x -30) -4(x -30)= 0

(x-30)(x-4)= 0

(x-30) = 0 or (x-4)= 0

x = 30 or x= 4

The value of x cannot be less than 10, so x= 30

Hence, the time taken by B to finish the work in 30 days.

The moral values reflected in this question which are to be adopted in our life is UNITY.

HOPE THIS WILL HELP YOU...