Question

Which term of the A.P. 5, 15, 25......... will be 60 more than its 9th term.​

Answer 1

Answer:

There cannot be any term as 60

Step-by-step explanation:

Its because you see the difference between the terms is 10, and the first term is 5

After applying formula for 9th term will be 85 and less than 85 would be 75, 65 but not 60.

Answer 2

${n}^{th} \: term = {15}^{th} \: term$

Step-by-step explanation:

HERE

a=t1 = 5

t2 = 15

t3 = 25

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TO FIND

Which term will be 60 more than its 9th term

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To find that which term will be 60 more than its 9th term

we have to find 9th term first

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We know that,

Common Difference ( d ) = t2 - t1

Common Difference ( d ) = 15 - 5

Common Difference ( d ) = 10

Common Difference ( d ) = 10

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We know that,

an = a1 + ( n - 1 ) × d

a9 = 5 + ( 9 - 1 ) × 10

a9 = 5 + 8 × 10

a9 = 5 + 80

a9 = 85

a9 = 85

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We have to find 60 more than its 9th term

Means

an = 60 + a9

a1 + ( n - 1 ) × d = 60 + 85

5 + ( n - 1 ) × 10 = 60 + 85

5 + 10n - 10 = 60 + 85

10n - 10 - 5 = 60 + 85

10n - 5 = 145

10n = 145 + 5

10n = 150

n = 150 / 10

n = 15

n = 15

${n}^{th} \: term = {15}^{th} \: term$