Question

Steve can paint a school room in 4hr. Miguel and Jamal can each paint a school room in 3 hr. How long will it take the three of them working together to paint 22 school rooms?

Answer 1

we know that

Steve can paint a schoolroom in 4hr

100% of the work ------> 4 hours

so

In one hour ------> (100/4=25%)

Miguel can paint a schoolroom in 3 hours

100% of the work -----> 3 hours

so

In one hour ----> (100/3)%

Jamal can paint a schoolroom in 3 hours

100% of the work -----> 3 hours

so

In one hour ----> (100/3)%

working together

In one hour -----> 25%+(100/3)%+(100/3)%=275/3 % (91.67%)

Applying proportion

Find out how long to make 100% of the work

1/(275/3)=x/100

solve for x

x=300/275

x=1.09 hours

Multiply by 22 schoolrooms

(300/275)*22=24 hours

the answer is 24 hours