Question

Dan mows 1/4 of his grandmother's lawn and uses 1/2 gallon of gas. What fraction of the lawn can Dan mow per gallon?

(A) 1/8
(B) 1/6
(C) 1/2
(D) 3/4

Answer 1

`(1)/(2)` of the grandmother's lawn Dan can mow per gallon.

Option C

Solution:

Given that, mowing
`(1)/(4)` uses
`(1)/(2)` gallon of gas.

To find: The fraction of the lawn can Dan mow per gallon

According to unitary method,

`(1)/(2)` gallon of gas is required to mow
`(1)/(4)` of lawn that is
`(1)/(2)\rightarrow (1)/(4)`

Therefore, 1 gallon of gas will be required to mow
`(1)/(2)*2\rightarrow (1)/(4)\frac2`

`\Rightarrow1 \text{ gallon }\rightarrow (1)/(2) \text{ of lawn}`

Therefore, one gallon will be enough to mow
`(1)/(2)` of lawn.

Unitary method:

The unitary method is a technique to solve a problem by finding the value of a single unit first, and then finding the required value by multiplying the single unit value. In essence, this method is used to find the value of a unit from the value of a multiple, and hence the value of a multiple.