Average of five numbers is 36. The average of first two numbers is 1.5 times of the average of last three numbers. What is the sum of first two numbers?

Correct option is D

Given:

Average of five numbers is 36.

The average of first two numbers is 1.5 times of the average of last three numbers.

Formula Used:

average = $$\frac{sum of data}{number of data}$$

Solution:

sum of five number =5$$\times$$average of five number 

= 5$$\times$$36

                                 = 180

  let average of last three numbers = 2x

so average of first two number = 1.5$$\times$$2x

                                                    =3x

sum of last three numbers = 3$$\times$$average of five number 

                                         =3$$\times$$2x

                                         =6x

sum of first two number = 3x$$\times$$2

                                        =6x

sum of all five numbers = 6x+6x =180

                                        12x=180

                                           x=15

so sum of first two  =6x 

                                =6$$\times$$15

                               =90