Question

Find the sum of 20terms of arithmetic series 5+10+15+... using the suitable formula​

Answer 1

Answer:

we know that a=5 and d=5 and s20=?

so sn=n/2{2a+(n-1) d}

s20=20/2{2×5+(20-1) 5}

s20=10{10+(19) 5}

s20=10{10+95}

s20=10(105)

s20=1050

Step-by-step explanation: