A boy is mowing a rectangular lawn 40ft long and 30ft wide. He has cut all of it except for a rectangle that is 20ft long and 15ft wide. What fractional part of the lawn remains uncut?

1/4

Step-by-step explanation:

Find the area of the full rectangle:

=> 40 x 30 = 1200

Find the area of the uncut part:

=> 20 x 15

=> 300

Make these numbers as a fraction.

=> 300 / 1200

=> 3/12

=> 1/4

So, 1/4 part remains uncut.

1/4 of the lawn is uncut.

Step-by-step explanation:

To find the fractional part of the uncut lawn:

Area of the rectangular lawn = 40 × 30 = 1200 ft²

Area of the uncut lawn = 20 × 15 = 300 ft²

300 ft² out of 1200 ft²:

300/1200 = 1/4

1/4 of the lawn is uncut.