- A boat can travel at 20 km/hr in still water. It travelled 144 km downstream in a river and then returned to the same place, taking 40 hours. The rate of flow of river is
144= 40[202-v2] / (2*20)
- A man pays Rs. 6.40 per litre of milk. He adds water and sells the mixture at Rs. 8 per litre, thereby making 37.5% profit. The proportion of water to milk received by the customers is
- The concentration of Juice in three different mixtures (juice and water) is 1/2 ,1/2 and 4/5 respectively. If 4 litres, 3 litres and 2 litre are taken from these three different vessels and mixed. What is the ratio of juice and water in the new mixture?
Quality of juice=(4*1/2+3*1/2+2*4/5)
Quality of water=(4+3+2)-5.1
- A water tank normally takes 10 hours to be filled by a tap but due to leakage, it takes another 2 hours. In how many hours will the leak empty a full water tank?
- A water tank has three taps A, B and C. A fills four buckets in 24 minutes, B fills 8 buckets in 1 hour and C fills 2 buckets in 20 minutes. If all the taps are opened together a full tank is emptied in 2 hours. If a bucket can hold 5 litres of water, what is the capacity of the tank?
A bucket can hold 5 litre.
Then A fills 4*5=20litres in 24min
In 1hr A fills 20/24*60=50litres
In 1hr B fills 8*5=40litres
C fills 2*5=10litres in 20min
In 1hr C fills 10/20*60=30litres.
All 3 open it empty 50+40+30=120litres in 1 hr.
Full tank emptied in 2 hrs.
Then Capacity of the tank is 120*2=240litres.
- Susan starts working on a job and continues for 20 days and completes 42% of the work. To complete the work, he employs Sameer and together they work for 10 days and completed the work. What will be the efficiency ratio of Susan and Sameer?
Susan 20days—-42% work
So total work done by susan=42+21=63%.
Then Sameer’s work 100-63=37%.
Ratio of efficiency in 10days=21:37.
- X borrowed Rs. 10,000 from his friend at 15% per annum simple interest. He lent it to Y at the same rate but compounded annually. Find his gain after two years.
CI =10000[(1+15/100)2 -1] =10000*(23/20*23/20 -1)
- In a test, a candidate secured 420 marks out of maximum marks ‘x’. If the maximum marks ‘x’ had been converted into 300 marks, he would have secured 252 marks. What was the maximum marks of the test?
- How many 4-letter words with or without meaning, can be formed out of the letters of the word, ‘LOGARITHMS’, if repetition of letters is not allowed?
LOGARITHMS contains 10 different letters.
Required number of words
= 10 x 9 x 8 x 7
- Four circular cardboard pieces, each of radius 7 cm are placed in such a way that each piece touches two other pieces. The area of the space enclosed by the four pieces is
Area=[14*14 -4*22/7*7*7*90/360] =196-154