Mixed Concepts

Reena climbs up 5 stairs every second and then climbs down 2 stairs over the next second. How many second will she take to climb 60 stairs?

• 30 seconds

• 40 seconds

• 25 seconds

• 20 seconds

A tanker contains 500 litres of milk. Due to a small hole in the tanker, the quantity of milk is decreasing at the rate of 9 litres every hour. What will be the quantity of milk after 10 hours?

• 491 litres

• 410 litres

• 90 litres

• 450 litres

• -67

• 53

• 67

• -53

A hiker is descending 152 m every 8 minutes. What will be hikers change in elevation in half an hour? Write as an integer.

• -4560m

• -76m

• -570m

• -1216m