# Maths (srithematic progression)

If the 4th term of an A.P is twice the 8th term, prove that the 10th term is twice the 11th term.

1. 👍 2
2. 👎 0
3. 👁 1,211
1. 4th term --- a + 3d
8th term ---- a + 7d

a+3d = 2(a+7d)
a+3d = 2a + 14d
-a = 11d
a = -11d

11th term = a + 10d
= -11d + 10d
= -d

10th term = a + 9d
= -11d + 9d
= -2d = twice -d = twice 11th term

1. 👍 5
2. 👎 4

## Similar Questions

1. ### Math

The sixth term of an A.P. is 5 times the first term and the eleventh term exceeds twice the fifth term by 3 . Find the 8th term ?

2. ### Maths

The 10th term of an a.p is -27 and the 5th term is -12 what is the 18th term? Find also the sum of its 25 term

3. ### FURTHER MATHS

The 8th term of a linear sequence is 18 and 12th term is 26.find the first term,common difference and 20th term

4. ### Arithmetic Progression

In an AP the 6th term is half the 4th term and the 3rd term is 15. a. Find the fist term and the common difference. b. How many times are needed to give a sum that is less than 65?

1. ### Geometry

The 8th term of a(GP) is 640. If the first term is 5, find the common ratio and the 10th term?

2. ### Core mathematics

The 4th term of an A.P.is 37 and the 6th term is 12 more than the 4th term.find the 1st and the 7th term of the sequence.

3. ### Utech

The 6th term of an A.P is twice the third and the first term is 3. Find the common difference and the 10th term.

4. ### Math

The second and seventh term of a g.p are 9 and 1/2 respectively.find the common ratio, first term and 10th term

1. ### arithmetic

The 8th term of an A P is 5times the third term while the 7th term is 9 greater than the 4th term.what are the first five term

2. ### math

in an ap the difference is between the 8th and 4th term is 20 and the 8th term is one and the half times the fourth term what is the common difference

3. ### Utech

The 9th term of an Arithmetic Progression is 8 and the 4th term is 20. Find the first term and the common difference.

4. ### math

The 3rd term of a geometric progression is nine times the first term.if the second term is one-twenty fourth the 5th term.find the 4th term. solution ar^2=9a r=sqr of 9 r=3.pls help me on how to get the first term(a)