Question

how many multiples of 4 lie between 10 and 250

Answer 1

248 Since difference is same, it is an AP Here a = 12 , d = 4 Last term = an = 248 We need to find n an = a + (n – 1) d an = a + (n – 1) d 248 = 12 + (n – 1) 4 248 = 12 + n (4) – 1 × 4 248 = 12 + 4n – 4 248 – 12 + 4 = 4n 236 + 4 = 4n 240 = 4n n = 240/4 n = 60 So, 60 multiples of 4 lie between 10 and 250.

Answer 2

Multiples of 4 --

12 , 16 ...... 248

a = 12 and d = 4

Tn = 12 + ( n - 1 ) * 4

248 = 12 + ( n - 1 )*4

248 - 12 /4 = n - 1

59 = n -1

n = 60 Ans.