A tank is fitted with 8 pipes, some of them that fill the tank and others that are waste pipe meant to those that empty the tank can empty it in 6 hours. If all the pipes are kept open when the tank is full, it will take exactly 6 hours for the tank to empty. How many of these are these are fill pipes?
Rehana leaves her home early in the morning so that she can reach her office on time. If she walks at the rate of 7 km/hr then she reaches her office 8 minutes late. But, if she walks at a speed of 8 km/hr, then she reaches her 4 minutes early. What is the distance in km between Rehana's house and her office?
Certain numbers of children were playing a game of football. There was a trial taking place on the field. In this trial the probability that a goal is scored is 2/5. The probability that a gril hits a goal is 7/10 whereas the probability than a boy hits a goal is 1/5. What will be the probability that not only a goal is hit but it is also hit by a boy?
Which of the following number is not a prefect square?
What is the radius of the in-circle of the triangle whose sides measure 5 12 and 13 units?
If-2
A car averages 25 miles per gallon of gasoline when driven in the city and 40 miles per gallon when drives on the highway. According to these rates, which of the following is closest to the number of miles per gallon that the car averages when it is driven 10 miles in the city and then 50 miles on the highway?
Annie invested a certain sum of money in a bank that paid simple interest. The amount grew to Tk 240 at the end of 2 years. she waited for a another 3 years and got a final amount of Tk 300. What was the principal amount that she invested at the beginning?
In what ratio should a 20% methyl alcohol solution be mixed with a 50% methyl alcohol solution so that the resultant solution has 40% methyl alcohol in it?
If the average of a and b is 45, and the average of b and c is 35, then (a-c)=?
Marium has n chocolates, where n is an integer such that 20
A group of 10 people plan to contribute equally to pay for a friend's gift that costs G dollars. If n additional people want to contribute to pay for the gift, the required contribution per person will be reduced by how many dollars?
A box contains 2 white balls, 3 black balls and 4 red balls. In how many ways can 3 balls be drawn from the box, if at least one black ball is to be included in the draw?
A bank offers 5% compound interest calculated on half-yearly basis. A customer deposits Tk. 1600 each on 1st July of a year. At the end of the year, how much he would have gained as interest?
Two number M and N are such that the sum of 5% of M and 4% of N is two-third of the sum of 6% of M and 8% of N. What is the ratio of M and N?
Ranu and Rabu appeared at an examination. Rabu secured 9 marks more than Ranu and her marks was 56% of the sum of their marks. The marks obtained by both of them are ---
In a class, 20% of the students are below 20 years of age. The number of students above 20 years of age is two-third of the number of students of 20 years of age which is 48. What is the total number of students in the class?
A large cube is formed from the material obtained by melting three smaller cubes of 3,4 and 5 cm side. What is the ratio of the total surface areas of the smaller cubes and the large cube?
Two trains of the same length running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively andhey cross each other in 23 seconds. What is the ratio of their speeds?
From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done?