Discover answers to your questions with Westonci.ca, the leading Q&A platform that connects you with knowledgeable experts. Get detailed and accurate answers to your questions from a community of experts on our comprehensive Q&A platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

If the 3rd term in an arithmetic sequence is 10 and the sum of the 1st 6 terms is 72. The fifth term is.

Sagot :

Answer:

5th term = 18

Step-by-step explanation:

a1    +    a1+d      a1 + 2*d      a1+3d      a1 + 4*d     a1 + 5d

a1 + 2d = 10

6*a1 + 15d = 72

Multiply the first equation by 6

6a1 + 12d = 60

Write the above equation underneath the second equation

6a1  + 15d = 72

6a1 + 12d = 60                Subtract

3*d = 12                            Divide by 3

d = 12/3

d = 4

a1 + 2d = 10

a1 + 2*4 = 10

a1 + 8 = 10                        Subtract 8 from both sides

a1 - 8 = 10- 8

a1 = 2

The fifth term is

t5 = 2 + 4*4

t5 = 18