Question

For an A.P., if d = 11, then t17 - t15 =?

Answer 1

Answer: 22

Step-by-step explanation:

T17 = a + (17-1)11

T17 = a + 176.

And

T15 = a + (15-1)11

T15 = a + 154

So,

T17 - T15 = a + 176 - (a + 154)

= a + 176 - a - 154

= 176 - 154

= 22

Answer 2

Answer:

22

Step-by-step explanation:

a+(n-1)×d

a+(17-1)11

a+(16)×11

a+176

a+(n-1)×d

a+(15-1)×11

a+(14)×11

a+154

so that,

t¹⁷-t¹⁵= a+176-(a+154)

t¹⁷-t¹⁵= a+176-a-154

t¹⁷-t¹⁵= 176-154

t¹⁷-t¹⁵=22