In a class of 100 students, the average weight is 30 kg. If the average weight of the girls is 24 kg and that of the boys is 32 kg, then what is the number of girls in the class?
In a school , 391 boys and 323 girls have been divided into the largest possible equal classes , so that each class of boys numbers the same as each class of girls . What is the number of classes ?
Mohit and Anshu invested some money in a business in the ratio 8 : 15 respectively. After 9 months Mohit withdraws his capital. If they receive profits in the ratio 4 : 5, then for how many months did Anshu invest in the business?
A ladder is resting against a vertical wall and its bottom is 2.5 m away from the wall. If it slips 0.8 m down the wall, then its bottom will move away from the wall by 1.4 m. What is the length of the ladder?
In the figure, B and C are the centres of the two circles. ADE is the common tangent to the two circles. If the ratio of the radius of both the circles is 3:5 and AC= 40, then what is the value of DE?