Question

The first term of an a.P is 5, the last term is 45 and the sum 400. Final number of terms and the common difference.

Answer 1

Step-by-step explanation:

Sum= 400

first term (a)= 5

an=45

sum (sn) = n/2(a+an)

400=n/2(5+45)

800 = n(50)

800/50 = n

16 = n

thus final number of terms = 16

an = a+(n-1)d

45 = 5+(16-1)d

45-5 = 15d

40 = 15d

40/15 = d

8/3 = d

common difference = 8/3

Answer 2

Answer:

Step-by-step explanation: