Question

Toby is painting his apartment. He has 4 gallons of paint. He uses 3/4 gallon for each wall. How many walls can he paint if he uses up all the paint? 5 1/2 walls5 1/3 walls 5 1/4 walls5 walls6 walls

Answer 1

We can answer this question in different ways. We can pose the problem as follows:

We posed the question as follows: with 3/4 of a gallon Toby can paint a wall, then with 4 gallons: how many can he paint?

Then, we can solve it using an operation called cross multiply as follows:

`x\cdot(3)/(4)\text{gallon}=4\text{gallon}\cdot1\text{wall}\Rightarrow x\cdot(3)/(4)=4\cdot1`

If we multiply both sides of the equation by 4/3, we have:

`x\cdot(3)/(4)\cdot(4)/(3)=4\cdot1\cdot(4)/(3)\Rightarrow x\cdot(4)/(4)\cdot(3)/(3)=(4\cdot4)/(3)\Rightarrow(4)/(4)=1,(3)/(3)=1`

Then, we have:

`x=(4\cdot4)/(3)\Rightarrow x=(16)/(3)=(15)/(3)+(1)/(3)\Rightarrow x=5+(1)/(3)\Rightarrow x=5(1)/(3)`

In summary, therefore, Toby can paint 5⅓ walls using the 4 gallons of paint he has.