Question

A man needs to prepare 7 plates of french fries for his friends. He takes 15 minutes to prepare 1 plate. If he started by 11 O'clock by what time he will be able to finish preparing all the plates?

• A. Quarter past 12
• B. Half past 12
• C. 12 O'clock
• D. Quarter to 1

Answer 1

The correct option is D Quarter to 1

Time taken for preparing 1 plate
= 15 minutes

Time taken for preparing 7 plates
= 15 $\times$ 7
= (8 + 7) $\times$ 7
= 8$\times$ 7 + 7 $\times$ 7
= (2+6) $\times$ 7 + (3+4) $\times$ 7
= 2 $\times$ 7 + 6$\times$7 + 3 $\times$7 + 4 $\times$7
= 14 +42 +21 +28
= 105 minutes

1 hour = 60 minutes
105 minutes = 60 minutes + 45 minutes
= 1 hour + 45 minutes

After 1 hour time will be 12 O'clock.

Again after 45 minutes time will be 12:45 or Quarter to 1