Question
The radii of two concentric circles are 20 cm and 25 cm.
A straight line PQRS intersects the larger circle at the points P and S and intersects the smaller circle at the points Q and R. If QR = 32 cm, then the length (in cm.) of PS is:(Approx.)Solution
In the right triangle OQM. OM = √ (20²- 16²) = √144 = 12cm In the right triangle OMS. Let RS = x cm So, (25) ² = (12) ² + (x + 16) ² (x + 16) ² = 625 – 144 = 481 x + 16 = 21.9 x=21.9 - 16 =5.9 x = 5.9 So, PS = 2 × (16 + 5.9) = 43.8 cm
A runner travels from point ‘E’ to ‘F’ at a constant speed. If the speed was increased by 12 km/h, it would have taken 2.5 hours less to cover t...
A car travels at 60 km/h to reach its destination on time. If it travels at 65 km/h, it will reach the destination 30 minutes ear...
Find the distance travelled (in km) by the truck to reach point B from point A, if a car cover 45% the same distance in 2 hours 42 minutes and a truck c...
Abhishek, Yogesh and Sumit start from the same place and travel in the same direction at the speed of 40 km, 60km and 90km per hour respectively. Yoges...
A boy goes to school at 12 km/Hr and return at a speed of 11 km/hr. If he takes 23 hrs in all. Find the distance from his village to school?
The speed of a car is 25% more than that of a bike. Both of them start from a same point. After travelling for 6 hours, the speed of the bike is increas...
In a 20 km race, A, B, and C are running at constant speeds. If A finishes the race 4 km ahead of B, and B finishes 4 km ahead of C, by how many meters ...
- How far will 'Puneet' travel by the time he catches up to 'Bittu', given that 'Puneet' starts 90 km behind and moves at 45 km/h while 'Bittu' moves at 30 k...
A car running with a speed of 50 km/hr takes 8 hours to go from 'A' to 'B'. If on the way back from 'B' to 'A', the car takes 20% less time than it take...
If a person walks 20% more than of his usual speed, reaches his distance 90 minutes before. If the destination is 459 km away, then the usual speed of a...
