Question

If 1, a, b, 13 are in AP, find a and b.
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Answer 1

Answer:

a=5 and b=9

Step-by-step explanation:

a-1=13-b

a+b=14------------1

and also,

b-a=13-b

2b-a=13-----------2

From 1 and 2,

we get,

a=5 and b=9

Answer 2

Answer:

a = 5 , d = 9

Step-by-step explanation:

1 , a , b , 13

a - 1 = 13 - b

a + b = 14 -------(1)

b - a = 13 - b

2b - a = 13 ------(2)

adding both equation we get:

a + b = 14

-a + 2b = 13

3b = 27

b = 9

Putting b value in eq 1

a + b = 14

a + 9 = 14

a = 14 - 9

a = 5