Q15 of 85 Page 110

If T3 = 8, T7 = 24, then T10 = _____

We have, T3 = 8


And recall that, Tn = a + (n – 1)d


So we have, T3 = a + (3 – 1)d


8 = a + 2d ……(1)


We also have, T7 = 24


And T7 = a + (7 – 1)d


24 = a + 6d …… (2)


From (1), we have that, a = 8 – 2d


So we put the value of a in (2)


24 = 8 – 2d + 6d


24 – 8 = 4d


16 = 4d


d= 4


now, putting value of d in (1),


8 = a + 2(4)


8 = a + 8


a =0


now, T10= a + (10 – 1)d


T10= 0 + 9 × 4


T10= 36


correct option is (d).

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