Question

A and B can paint a wall in 20 hours and 24 hours respectively. If C helps them, they can paint the wall only in 8 hours. C alone can paint it in?

REPLY ASAP!!!​

Answer 1

Answer:

20 + 24+8 = 52

Step-by-step explanation:

because  20 + 24= 44

if we add 44 + 8 = 52

Answer 2

Answer:

C alone can paint it in 30 Hours.

Step-by-step explanation:

Given,

  A can Paint a wall in 20 Hours and B can Paint a wall in 24 Hours.

If C helps Them, They can Paint the wall in 8 Hours.

We need to find time taken by C alone to Paint the Wall.

Sol: A can Paint a the wall in 20 Hours.

       i.e.

                   $A=20 Hours$

      B can Paint the wall in 24 Hours.

      i.e.

                 $B=24 Hours$

      and A, B and C can Paint the wall in 8 Hours.

       i.e.

                 $\frac{1}{A} +\frac{1}{B}+\frac{1}{C}=\frac{1}{8} \\\frac{1}{20} + \frac{1}{24} +\frac{1}{C} =\frac{1}{8} \\\frac{1}{C} =\frac{1}{8} -[\frac{1}{24} +\frac{1}{20}]\\\frac{1}{C}=\frac{1}{8} -\frac{1}{24} -\frac{1}{20} \\\frac{1}{C} =\frac{15-5-6}{120} \\\frac{1}{C} = \frac{15-11}{120} \\\frac{1}{C} = \frac{4}{120} \\\frac{1}{C} =\frac{1}{30} \\C=30$

     Thus, C can Paint the wall in 30 Hours.