Question
At the rate of any compound interest rate, it gets
tripled in 4 years, in how many years it will become 729 times its own?Solution
Let the principal be Rs. x, then Amount = 3x As we know, A = P (1+r/100)t 3x = x (1 + r/100)4 (1+r/100) = 4√3       ...i) Again, A = 729x, P = x 729x = x (1 + r/100)t (1+r/100) = t√729    ...ii) From equation (i) 4 √3= t√729 31/4 = 36/t Compare on powers. 1/4 = 6/t t = 24 years Smart Approach-       In 4th year = 3 times.  After T years =729=36 T=4×6=24 years.
70, 69, 73, 64,80, 55, ?
- 8, 12, 18, 27, ?
56, 27, 14.5, 6.25, ?, 1.0625
6, 7, 15, 46, 185, ?
What will come in place of the question mark (?) in the following series?
60, 110, 224, 463, ?, 1716
9 28 83 250 ? 2248
- What will come in place of the question mark (?) in the following series?
2, 5, 16, 47, 138, ? What will come in place of the question mark (?) in the following series?
12, 13, 27, ?, 329, 1646
17    18      14       ?      7       32
...74, 84, 64, 104, ?, 184
