Question

Su and nik while working together can complete a piece of work in 45 hours, while nik alone can compleet in 72 hours.How long su takes to complete

Answer 1

Step-by-step explanation:

let su be A and

nik be B

so according to given condition we can say that

◆A and B together complete a work in 45 hrs and

◆B alone can complete a work in 75 hrs

A + B = 45

B = 75

now here the total work is not given that is we will have to find the total work. For that we will have to find the L.C.M of 45 and 75 that it is 675

when 675 is total work

◆A + B = 675 ÷ 45 = 1hr work

◆A + B = 15

◆ B = 675 ÷ 75 = 1hr work

◆ B = 9

means we can say that

A + B = 15

B = 9

here A and B together can doy

15 work where B alone can do 9 work

A + 9 = 15

A = 6

now 6 is 1 hr work

675 ÷ 6 = total time required by A

112.5 means

112 : 30 hrs will required by Su to complete a work

Answer 2

Answer: Su takes to complete the work in 12.5 hours.

Explanation

Given-Su and nik together can complete a piece of work in 45 hours nik alone can complete in 72 hours.

Find how long Su takes to complete

Solution-Su and nik complete together-45 hours nik can complete alone =7 hours.

$Su +nik-45$ ______   5  225 (total work)

$nik-75$    __________  3

Efficiency of Su+nik=5

Nik=3

So, the efficiency of So of 2.

Su, take to complete the work=$\frac{TW}{Efficiency}$

$=\frac{225}{2}$

$=112.5 hours$

Hence, Su takes to complete the work in 112.5 hours

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