Question

How do I solve this problem?

Answer 1

Explanation:

Solution:

Given,

t1( first term ) a = -15

t2( second term ) b = -9

CD(Common Difference) = ?

We know,

CD = b - a

= -9 - ( - 15 )

= -9 + 15

= 6

Now,

t1 = -15

t2 = -9

t3 = -3

t4 = 3

t5 = a + ( n - 1 )CD

= -15 + ( 5 - 1 ) 6

= -15 + 24

= 9

t50 = a + (n - 1 ) CD

= -15 + ( 50 - 1 ) CD

= -15 + 49 × 6

= -15 + 284

= 269

So the sum of t50 is 269.