Question

if for an ap t7=20 ,S20=610 then find t10 and S15​

Answer 1

t10{1} s15{2}

t7=20

t=20÷7

t=2.85. {3}

s20=610

s=610÷20

s=30.5. {4}

put {3} into {1}

t10 = 2.85

t= 2.85 ÷10

t=28.5

put {4} into {2}

s15=30.5

s=30.5×15

s=457.5