Question
A meter-long pipe is made whose internal diameter is
equal to the outer radius. How much material (cubic units) will be required to make the pipe if it holds 88/7m³?Solution
Let the radius of the inner cylinder be r and the radius of the outer cylinder be R. 2r = RÂ In this figure, the amount of water that will flow will be equal to the volume of the inner cylinder. 
The volume of cylinder = Ï€r2h 88/7 = 22/7 ×1× r2 r = 2 , then R = 4 Materials used to make pipe (volume) = volume of outer cylinder - volume of the inner cylinder = Ï€R2h-Ï€r²h V = Ï€h (R2 -r2 ) V = 22/7 ×1×(16-4) V = 22/7 ×1×12 V = 37.7 m³Â
What will come in place of the question mark (?) in the following series?
1528, 1416, 1204, ?, 480, -32
143 Â Â Â Â 119Â Â Â Â 107Â Â Â Â 101Â Â Â Â Â 98Â Â Â Â ?
96 89 ? 90 94 91
...What value should come in the place of (?) in the following number series?
19, 235, 260, 324, 333, ?
What will come in place of the question mark (?) in the following series?
305...
In each of the following number series, one term is missing. Find the missing term.
3, 5, 20, 24, 144, 150, ?
1029, 1030, 1039, 1064, ?, 1194
75, 80, 95, ?, 155, 200
What will come in place of the question mark (?) in the following series?
1515, 184, ?, 455, 967, 624
7 29 61 ? 211 349
...
