Question

For an ap the first and last terms are 13 and 216 common difference is 7 how many terms are tjere in an ap find the sum of all the terms

Answer 1

a=13,tn=216,d=7,n=?

tn=a+(n-1)d
216=13+(n-1)7
216-13=(n-1)7
203÷7=n-1
19=n-1
19+1=n
20=n