DRDO Multi tasking staff Model paper 5

Tips & Tricks
Given that,
The average temperature of the town in the first four days of a month = 60 degrees.
The average for the second, third, fourth and fifth days = 64 degrees.
The temperatures of the first and fifth days were in the ratio 3 : 7.
According to the question,
Sum of temperatures on 1st, 2nd, 3rd and 4th days
⇒ 60 × 4
⇒ 240 degrees ... (1)
Sum of temperatures on 2nd, 3rd, 4th and 5th days
⇒ 64 × 4 = 256 degrees ... (2)
Subtracting (1) From (2), we get
Temperature on 5‌th day - temperature on 1‌st day
⇒ (256 - 240)°
⇒ 16 degrees
Given, The temperatures of the first and fifth days were in the ratio 3 : 7.
Let the temperatures on 1st and 5th days be 3x and 7x degrees respectively.
Then,
⇒ 7x - 3x = 16
⇒ x = 4
So, temperature on 5‌th day is 7x.
Then,
Temperature on 5‌th day
⇒ 7 × 4
⇒ 28 degrees
∴ The temperature on the fifth day is 28 degrees.