Algebra
Practice Questions on Algebra
Q21) Find the sum of n terms of the series 1.2.4 + 2.3.7 + 3.4.10 + ... n terms.
Use substitution method (Substitute different values of n starting from n = 1). Hence, option 2. Q22) Solve for y: 4y - 9 × 2y + 8 = 0 1) 1,3 2) 0,3 3) 0,-1 4) -1,3
Check options. Hence, option 1. Q23) Sum of n terms of an A.P. is  . What is the common difference.1) 2 2) 4 3) 3 4) 5  = S1 = 4 i.e. T1 = 4 S2 = 11 i.e. T2 = 7 Common difference = T2 - T1 = 7 - 4 = 3 Hence, option 3. Q24)  ?1) 1/(a - 2b) 2) (a + 2b) 3) (2a + b) 4) (a + 4b)  Hence, option 2. Q25) How many 3 digit numbers are divisible by 6? 1) 151 2) 166 3) 160 4) 150
3 digit numbers divisible by 6 are: 102, 108, 114,....., 996 This is an A.P. with a = 102, d = 6, L = 996 Let n be the number of terms,  = 996 996 = 102 + (n - 1)×6 On solving, n = 150 Hence, option 4. |