Question
Two trains C and D started from point A and B
respectively. Speed of train D is 21 km/hr more than that of train C. Total distance between point A and B is 495 km. If both the trains meet in 3 hours 40 minutes, then find the speed of train D (in km/hr).Solution
Let the speed of train C be ‘x’ km/hr. Then, speed of train D = (x + 21) km/hr Time = 3 hours 40 minutes = 3(40/60) = 3(2/3) = 11/3 hrs  According to the question, => Speed = Distance/ Time => (x + x + 21) = 495/(11/3) => 2x + 21 = 45 × 3 => 2x = 135 - 21 => x = 57 Speed of train C = x = 57 km/hr Speed of train D = (x + 21) = 78 km/hr
Average of first 4 numbers is 1.5 times the average of the next 2 numbers. If the average of all 6 numbers is 30, find the sum of the last 2 numbers.
- Average of 10 quantities is 35. If two extra quantities are added whose average is 'x', the new average rises by 10%. Find the value of 'x'.
- The average height of a group of 30 players was recorded as 168 cm. Later it was discovered that 172 was wrongly written as 182 and 160 was written as 150....
The average age of a group of 10 friends is 27 years. If one friend leaves the group, the average becomes 25years. Find the age of the friend who left t...
A batsman had an average of 82 runs per match in the first 25 matches. In his next 15 matches, he scored runs with an average of ‘x’ runs per match ...
The average of 8 consecutive even numbers written in ascending order is 17. What is the average of the last three numbers, 36 and 53 ?
The average of two consecutive even numbers is 61. If the smaller number is increased by 18% and the larger number is decreased by 18%, then find the di...
The average of two consecutive even numbers is 79. If the smaller number is increased by 50% and the larger number is decreased by 50%, then find the di...
The average price of two laptops, namely 'D' and 'E' is Rs. 65,500 whereas the average price of laptops 'E' and 'F' is Rs. 70,000. If the average price ...
- The average of two numbers is 3 more than the smaller number among them. If the greater number is 25% more than the smaller number, then find the sum of th...
Relevant for Exams:
