Question
A boat can travel 80 km downstream in 8 hours, and it
can travel the same distance upstream in 10 hours. What is the speed of the boat in still water?Solution
Let the speed of the boat in still water be x km/h, and the speed of the stream be y km/h. Downstream speed = x + y Upstream speed = x - y We know: Time downstream = Distance / Speed = 80 / (x + y) = 8, so x + y = 10 Time upstream = Distance / Speed = 80 / (x - y) = 10, so x - y = 8 Now, solve these two equations: x + y = 10 x - y = 8 Add the two equations: 2x = 18 ⇒ x = 9 km/h So, the speed of the boat in still water is 9 km/h. Correct Option: c) 9 km/h
What is the unit digit of the number 'Z' obtained by subtracting the largest two-digit prime number from the least common multiple (LCM) of all single-d...
The least number which when divided by 7, 12, 15 and 20 leave zero remainder in each case and when divided by 26 leaves a remainder of 4 is:
Three numbers are in the ratio 6:9:10 respectively. If the HCF of the numbers is 3, then find the LCM of the numbers.
The LCM and the HCF of the numbers 25 and 40 are in the ratio:
LCM of two numbers is 12 times their HCF. The product of the numbers is 25920. What will be the maximum possible difference between the numbers?
The HCF of two numbers is 14. If their product is 5488, then how many such pairs exist?
The LCM of two natural numbers is 15 times their HCF. If the product of given two numbers is 13,500, then find the LCM of the numbers.
Find the difference between sum of digits of LCM and HCF of 28, 42 and 70.
The square of sum of two numbers is 36,864 and the sum of squares of the same two numbers is 21,024. If their H.C.F. is 12, then find their L.C.M.Â
What is the HCF of  (x4  - x2  - 6)   and  (x4  - 4x2  + 3) ?
(a)Â x2 Â - 3Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â (b)...
Relevant for Exams:
