# The temperature at 12 noon was 10°C above zero. If it decreases at the rate of 2°C per hour until midnight, at what time would the temperature be 8°C below zero? What would be the temperature at mid-night?

**Solution:**

(i) The temperature at 12 noon=10°C (given)

The temperature decreases 2°C = 1 hour (given)

The temperature decreases 1°C = 1/2 hour

The temperature decreases 18°C = 1/2 × 18

(From 10°C to 8°C below zero) = 9 hours

Total time = 12 noon + 9 hours

= 21 hours = 9 pm

Thus, at 9 pm temperature would be 8°C below zero.

(ii) The temperature at 12 noon = 10°C

The temperature decreases = 2°C every hour

The temperature decreases in 12 hours = -2°C × 12 = -24°C

At midnight, the temperature will be = 10°C + (-24°C) = -14 °C

Therefore, the temperature at mid night will be 14°C below 0.

**Video Solution:**

## The temperature at 12 noon was 10°C above zero. If it decreases at the rate of 2°C per hour until midnight, at what time would the temperature be 8°C below zero? What would be the temperature at mid-night?

### NCERT Solutions Class 7 Maths - Chapter 1 Exercise 1.4 Question 5

The temperature at 12 noon was 10°C above zero. If it decreases at the rate of 2°C per hour until midnight, at what time would the temperature be 8°C below zero? What would be the temperature at mid-night?

The temperature would be 8 degrees Celsius below zero at 9 PM, Temperature at the midnight will be 14 degrees Celsius below zero