A sum of 8550 is to be paid in 15 installments where each installments is 10 more than the previous - Maths - Arithmetic Progressions

Question

A sum of 8550 is to be paid in 15 installments where each
installments is 10 more than the previous installment Find the
first installment and the last installment

Ajanta Trivedi · Accepted Answer

let the first installment be a , therefore the 2nd installment = a+10

since it forms an AP, with first term a and the common difference =10

sum of 15 installments $= \frac{15}{2} [2 a + (15 - 1) d] = \frac{15}{2} [2 a + 14 * 10] = 15 (a + 70)$

therefore

$15 (a + 70) = 8550 a + 70 = \frac{8550}{15} = 570 a = 570 - 70 a = 500$

thus the first installment is Rs. 500 and

the last installment i.e. 15th installment = a+(15-1)d

=500+14*10

=500+140

=640/-

hope this helps you.

A sum of 8550 is to be paid in 15 installments where each installments is 10 more than the previous installment.Find the first installment and the last installment.