The average temperature of the town in the first four days of a month

1.	The average temperature of the town in the first four days of a month was 58 degree. The average for the second, third, fourth and fifth days was 60 degree. If the temperatures of the first and fifth days were in the ratio 7 : 8, then what is the temperature on the fifth day? (A) 64 degree(B) 62 degree(C) 56 degree(D) None of these
Answer» The correct option is: (A) 64 degree Explanation: Let the temperatures on first, second, third, fourth and fifth day be x₁, x₂, x₃, x₄ and x₅, respectively. Sum of temperatures of first four days = 58 x 4 i.e., x₁ + x₂ + x₃ + x₄ = 232 ...(i) and sum of temperatures on second, third, fourth and fifth day = 60 x 4 i.e., x₂ + x₃ + x₄ + x₅ = 240 ...(ii) Subtracting (i) from (ii), we get x₅ - x₁ = 8 ...(iii) Also, temperature of first and fifth day were in the ratio 7 : 8. Let the temperatures be 7 k and 8 k respectively. From (iii), we have 8k - 7 k = 8 => k = 8 Temperature of fifth day - 8 x 8 = 64 degree

The average temperature of the town in the first four days of a month was 58 degree. The average for the second, third, fourth and fifth days was 60 degree. If the temperatures of the first and fifth days were in the ratio 7 : 8, then what is the temperature on the fifth day? (A) 64 degree(B) 62 degree(C) 56 degree(D) None of these

Answer»

The correct option is: (A) 64 degree

Explanation:

Let the temperatures on first, second, third, fourth and fifth day be x₁, x₂, x₃, x₄ and x₅, respectively.

Sum of temperatures of first four days = 58 x 4

i.e., x₁ + x₂ + x₃ + x₄ = 232 ...(i)

and sum of temperatures on second, third, fourth and fifth day = 60 x 4

i.e., x₂ + x₃ + x₄ + x₅ = 240 ...(ii)

Subtracting (i) from (ii), we get x₅ - x₁ = 8 ...(iii)

Also, temperature of first and fifth day were in the ratio 7 : 8.

Let the temperatures be 7 k and 8 k respectively.

From (iii), we have 8k - 7 k = 8 => k = 8

Temperature of fifth day - 8 x 8 = 64 degree