If it takes 5 men 20hours to brick a house, how long will it take 2 men to do the job if they work at the same rate?

50 hours.

Step-by-step explanation:

To solve these type of question we should always remember that man power is inversely proportionate to the work done.

That means if we double the manpower work done will be half. and when we reduce the manpower to the half time take to complete the work will be double.

It takes 5 men to brick a house = 20 hours

so 1 man will brick the house = 20 × 5

                                                = 100 hours

Therefore, 2 men will brick the house =  

                                                               = 50 hours.

hello :

by applying the distributive property :

6 × 4.3 = 6 × ( 4 + 0.3 )

            =   (6 ×   4) + (6 ×   0.3)

            = 24 + 1.8

6 × 4.3 = 25.8

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)