A class having three different sections P, Q and R with the students i

1.	A class having three different sections P, Q and R with the students in the ratio of 144 : 180 : 225 respectively and the marks scored by the classes is in the ratio of 45 : 51 : 36 then find the average of the whole class?1. 40.2782. 43.2783. 41.2784. 42.2785. 48.278
Answer» Correct Answer - Option 2 : 43.278 GIVEN: The students in the ratio of 144 : 180 : 225 ----(1) Marks scored by the classes is in the ratio of 45 : 51 : 36 ----(2) CONCEPT USED: ⇒ Ratio assumption & deviation method CALCULATION: The eq(1) can also be written as, The students in the ratio of 16 : 20 : 25 ----(3) Marks scored by the classes is in the ratio of 45 : 51 : 36 ----(4) We can solve this question by taking any assumed ratio. Let the assumed ratio be 40. The first ratio is +5 to 40 and of 16 students so we will multiply +5 x 16 = 80 ----(4) Second ratio is 51 which is +11 to 40 and number is 20 so we will multiply +11 x 20 = 220 ----(5) Third ratio is 36 which is -4 to 40 and number is 25 so we will multiply -4 x 25 = -100 ----(6) Adding eq(4), eq(5) and eq(6) and dividing by total numbers. ⇒ Deviation = (80 + 220 - 100)/61 ⇒ Deviation = + 3.278 Adding this deviation to assumed average we get 43.278 ⇒ Actual average = 43.278

A class having three different sections P, Q and R with the students in the ratio of 144 : 180 : 225 respectively and the marks scored by the classes is in the ratio of 45 : 51 : 36 then find the average of the whole class?1. 40.2782. 43.2783. 41.2784. 42.2785. 48.278

Answer» Correct Answer - Option 2 : 43.278

GIVEN:

The students in the ratio of 144 : 180 : 225 ----(1)

Marks scored by the classes is in the ratio of 45 : 51 : 36 ----(2)

CONCEPT USED:

⇒ Ratio assumption & deviation method

CALCULATION:

The eq(1) can also be written as,

The students in the ratio of 16 : 20 : 25 ----(3)

Marks scored by the classes is in the ratio of 45 : 51 : 36 ----(4)

We can solve this question by taking any assumed ratio.

Let the assumed ratio be 40.

The first ratio is +5 to 40 and of 16 students so we will multiply +5 x 16 = 80 ----(4)

Second ratio is 51 which is +11 to 40 and number is 20 so we will multiply +11 x 20 = 220 ----(5)

Third ratio is 36 which is -4 to 40 and number is 25 so we will multiply -4 x 25 = -100 ----(6)

Adding eq(4), eq(5) and eq(6) and dividing by total numbers.

⇒ Deviation = (80 + 220 - 100)/61

⇒ Deviation = + 3.278

Adding this deviation to assumed average we get 43.278

⇒ Actual average = 43.278