Question

In order to get a certain shade of blue paint, a mixer must have 5 parts white paint to 3 parts blue. If 4 gallons of paint must be mixed, how many gallons of white paint must be used?

3.7 gallons
2.5 gallons
1.9 gallons
1.5 gallons

Answer 1

Answer: 2.5 gallons.

Explanation:

Given : In order to get a certain shade of blue paint, a mixer must have 5 parts white paint to 3 parts blue.

Total paint mixed = 5+3= 8 parts

The ratio of white paint to the total mixture =
`\frac{\text{Parts of white colour}}{\text{Total parts of mixture }}`

`=(5)/(8)` (1)

Let x be the number of gallons of white paint.

If 4 gallons of paint must be mixed , then the ratio of white paint to the total mixture =
`=(x)/(4)` (2)

From (1) and (2) , we have

`(x)/(4)=(5)/(8)`

Multiply 4 on both sides , we get

`x=(5)/(8)*4=(5)/(2)=2.5`

⇒ x= 2.5

⇒ Number of gallons of white paint is required = 2.5 gallons.

Answer 2

Option B. 2.5 gallons of white paint must be used

Explanation:

In order to get a certain shade of blue paint, a mixer must have 5 parts white paint to 3 parts blue.

Total paint was mixed = 4 gallons.

5 parts white + 3 parts blue = 8 parts

divide it into 8 parts to get each part must be = 4 ÷ 8 = 0.5 gallons

It is given that 5 parts of white paint = 5 × 0.5 = 2.5 gallons

and 3 parts of blue paint was mixed = 3 × 0.5 = 1.5 gallons

Option B. 2.5 gallons of white paint must be used.