Question
Two classmates R and S stand at points U and V
respectively. R starts toward V from U at a speed of (x – 5) km/h. After 3 hours, S starts toward U from V at a speed of (x + 5) km/h. They meet exactly at the midpoint of UV. If UV = 360 km, find the time taken by R to go from U to V.Solution
ATQ, Distance covered by R in 3 hours = (x – 5) × 3 = 3(x – 5) km Remaining distance between them = 360 – 3(x – 5) = 360 – 3x + 15 = (375 – 3x) km Time of meet after S starts = (375 – 3x)/(2x) hours According to question, [(375 – 3x)/(2x)] × (x + 5) = 360/2 (375x + 1875 – 3x² – 15x) = 360x ⇒ –3x² + 1875 = 0 3x² = 1875 x² = 625 x = 25 Speed of R = 25 – 5 = 20 km/h Therefore, required time = 360/20 = 18 hours
What will come in place of the question mark (?) in the following series?
520, 519, 511, ?, 420, 295
Choose the missing term?
B, D, F, I, L, P, ?
22, 37, 63, 98, 148, ?
10, ?, 50, 100, 250, 500
226 231 466 ? 5606 28031
24 12 18 ? 157.5 708.75 3,898.125
168, 164, 155, 139, ?, 78
What will come in place of the question mark (?) in the following series?
15, 26, 39, 56, ?, 98
10,14,26,42,70,?
62, 87, 137, ?, 312, 437
