A roofing contractor can shingle a roof in half the time it takes his assistant. Working together, they can shingle the roof in 8 hours. How much time does it take the roofing contractor to finish the job alone

It will take him 12 hours working alone

Step-by-step explanation:

In this question, we are asked to calculate the time in hours it will take a roofing contractor to finish a job alone given the amount of time he and his assistant will finish the roof job.

We can identify from the question that he works 2 times as fast as his assistant. So let’s say he takes x hours, his assistant will take 2x hours

Now, let’s say the span of the roofing work is y meters.

His rate will be y/x and his assistant will be y/2x while their joint rate will be y/8

Now if their individual rates are added together, we will have the joint rate

Mathematically;

y/x + y/2x= y/8

y(1/x + 1/2x) = y(1/8)

1/x + 1/2x = 1/8

3x/2x^2 = 1/8

3/2x = 1/8

2x = 24

x = 24/2

x = 12 hours

answer: city needs 2.4 inches of rainfall more to match the record of 40 inches.

step-by-step explanation:

since we have given that

total annual rainfall a city record = 40 inches

this year, total rainfall recorded = 37.6 inches

number of inches of rainfall   is needed to match the record of 40 inches is given by

hence, city needs 2.4 inches of rainfall more to match the record of 40 inches.

oof

step-by-step explanation: