In each of the following questions, a series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series.
20. 7, 2 = 59, 5, 3 = 28, 9, 1= 810, 2, 1 = 13, 5,4 = ?

Options

A. 19
B. 9
C. 20
D. 239

Answer

A

Explanation

`7-2 = 5, 7 + 2= 9`
`rArr 7,2 = 59`
`5 - 3 = 2, 5 + 3 = 8`
`rArr 5, 3 = 28`
`9-1 = 8 , 9 + 1= 10`
`rArr 9,1 = 810`
`2- 1 = 1, 2 + 1 = 3`
`rArr 2,1 = 13`
Therefore,
`5 - 3 = 1 , 5 + 4 = 9`
`rArr 5,4 = 19`