Question

for an A.P if s10 =150and S9 = 126, t10​

Answer 1

s10=150

s9=126

t10=s10-s9

t10=150-126

t10=24

so t10 is 24.

Answer 2

Answer:

Step-by-step explanation:

S10=10/2+{2a+(10-1)d}

=>150=5+(2a+9d)

=>2a+9d=30 ....... (1)

S9=9/2+{2a+8d}

=>126=9/2+(2a+8d)

=>2a+8d=28 ...... (2)

From equation (1) and (2)

2a+9d-2a-8d=30-28

=>d=2

Put the value of d in equation (1)

2a+9×2=30

=>2a+18=30

=>2a=30-18

=>2a=12

=>a=6

Now, t10=a+(n-1)d

=>t10=6+(10-1)×2

=>t10=6+9×2

=>t10=6+18

=>t10=24