Question

-
A batsman has an average score of 20 runs in first 6 matches. From second to seventh
matches his average score was 21 runs. If he scores total 30 runs in first and seventh
matches, what is his score in 7th match?
(A) 18 runs
(B) 22 runs (C) 15 runs (D) None of these​

Answer 1

Answer:

18 runs option A is correct

Step-by-step explanation:

let the score in seven matches be x1, x2, x3....... , x7

given-

avergae of first six matches is 20 runs which means

(x1+x2+x3+x4+x5+x6)/6=20

x1+x2+x3+x4+x5+x6=120-----------1

average score from second to seventh matches is 21 runs

(x2+x3+x4+x5+x6+x7)/6 = 21

(x2+x3+x4+x5+x6+x7)= 126--------------2

x1+x7= 30 given in question------------3

from these 3 equations find x7

subtract equation 2 from equation 1

x7-x1= 6---------4

add eqn 3 and eqn 4

we will get

2x7= 36

x7= 18 runs