Question
The length of a rectangle is four times its breadth. If
its length is increased by 20 cm and breadth is increased by 20 cm, the area of the rectangle is increased by 900 cm2. Find the length of the rectangle.Solution
Let Breadth = x and Length = 4 x ∴ Original area = 4 x × x = 4 x² Now, New Area = ( 4 x +20 ) x (x +20) ∴ ( 4 x +20 ) × (x +20) - 4x² = 900 ⇒ 100x=900 – 400 ⇒ x= 5 ∴ l = 4 × 5 = 20cm
230 192 172 ? 122 100
...What value should come in the place of (?) in the following number series?
64, 80, 104, ?, 176, 224
97, 106, ?, 195, 411, 460
What will come in place of the question mark (?) in the following series?
29, 42, ?, 95, 135, 184
Find the missing term:
2, 6, 15, 31, 56, ?
32   48   96   ?   720   2520
82, 98, 130, 178, 242, ?
4 10 ? 62.5 156.25 390.625
...140, 146, 170, 224, ?, 470
7 47 ? 223 359 527
...