Question

If the ratio of 10th term of an Arithmetic Progression to its 5th term is 1 : 2, then a:d is______
a) 14:1
b) 1:14
c) 2:1
d) -14:1

No other Gyaan, definition -,-
​

Answer 1

Answer:

Given sum of 1

st

10 terms=4(sum of 1

st

5 terms)

∴S

10

=4S

5

2

10

[2a+9d]=4×

2

5

[2a+4d]

5[2a+9d]=10[2a+4d]

⇒10a+45d=20a+40d

⇒5d=10a

⇒

2

1

=

d

a

⇒a:d=1:2.

Answer 2

Answer:

(C) is correct

Step-by-step explanation:

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