Question

The average of 10 numbers is 25. The average of first three numbers is 22 1/3 and that of next five is 15 1/5. If the eighth be less than the ninth and tenth numbers by 5 and 11 respectively, then the tenth number is

Answer 1

28. Is correct answer

Answer 2

Hey Dear,

◆ Answer -

41 1/3

● Explanation -

Sum of first 3 numbers -

S1 = 3 × 22 1/3

S1 = 67

Sum of next 5 numbers -

S2 = 5 × 15 1/5

S2 = 76

Let x be 8th number, then 9th number will be x+5 and 10th will be x+11.

Total sum of all 10 numbers will be -

10×25 = S1 + S2 + x + x+5 + x+11

250 = 67 + 76 + 3x + 16

3x = 250 - 159

3x = 91

x = 30 1/3

Now 10th number is -

x+11 = 30 1/3 + 11

x+11 = 41 1/3.

Thus 10th number is 41 1/3.

Thanks dear...