Given that , The average of five results = 46
Sum total of five results = 5 × 46 = 230
and average of first four = 45.
Sum total of first four results = 4 × 45 = 180

Correct Option: A

Given that , The average of five results = 46
Sum total of five results = 5 × 46 = 230
and average of first four = 45.
Sum total of first four results = 4 × 45 = 180
So, fifth result = 230–180 = 50.

Let mother’s age = y years
The age of elder sister = 18 years
Father’s present age = 32 + 15 = 47 years
According to question ,
∴ 47 – y = 2 (18 – 15) = 6

Correct Option: B

Let mother’s age = y years
The age of elder sister = 18 years
Father’s present age = 32 + 15 = 47 years
According to question ,
∴ 47 – y = 2 (18 – 15) = 6
⇒ y = 47 – 6 = 41 years

According to question ,

Weight of teacher =		30 × 300	+ 40		kg
		1000

Correct Option: A

According to question ,

Weight of teacher =		30 × 300	+ 40		kg
		1000

Here , The average age of 40 boys = 16 years.
Total age of 40 boys initially = 16 × 40 = 640 years
Age of replaced boy = 17 years
Total age of 39 boys = 640 – 17 = 623 years
New total age = 40 × 15.95 = 638 years

Correct Option: B

Here , The average age of 40 boys = 16 years.
Total age of 40 boys initially = 16 × 40 = 640 years
Age of replaced boy = 17 years
Total age of 39 boys = 640 – 17 = 623 years
New total age = 40 × 15.95 = 638 years
∴ Age of new boy = 638 – 623 = 15 years

Let The temperature for Monday and Friday are 21y and 25y.
According to the question,
M + T + W + Th = 60 × 4 = 240° ..... (i)
T + W + Th + F = 63 × 4 = 252° ..... (ii)
By equation (ii) – (i),
F – M = 252° – 240° = 12°
⇒ 25y – 21y = 12°

Correct Option: C

Let The temperature for Monday and Friday are 21y and 25y.
According to the question,
M + T + W + Th = 60 × 4 = 240° ..... (i)
T + W + Th + F = 63 × 4 = 252° ..... (ii)
By equation (ii) – (i),
F – M = 252° – 240° = 12°
⇒ 25y – 21y = 12°
⇒ 4y = 12° ⇒ y = 12 ÷ 4 ° = 3°
∴ Temperature on Friday = 25y = 25 × 3 = 75°