Question
In a class of 40 students, the ratio of boys and girls
is 3 : 2 and the average marks scored by boys is 42 and by girls is 46. Then the average marks scored by the whole class is:Solution
1. Let the number of boys be 3x and girls be 2x, where 3x + 2x = 40 ⇒ x = 8. 2. Then, boys = 24 and girls = 16. 3. Total marks for boys = 24 × 42 = 1008. 4. Total marks for girls = 16 × 46 = 736. 5. Average marks for the class: 
A particle starts from rest and moves with uniform acceleration for 24 seconds. Let the distances covered during the first 8 seconds, the next 8 seconds...
Which polymer is used in the production of bullet-proof materials?
The force which opposes the relative motion between different layers of liquid or gases is called –
Which among the following nutrients is essential for the normal functioning of the thyroid gland?
A gas is compressed at constant temperature. Which of the following will decrease?
What happens to your weight when you are in a lift which goes down?
A wire carrying a current of 4.0 A is shaped into a circular arc of radius 8.0 cm. If the arc subtends an angle of 90° at the center, what is the magn...
A constant retarding force of 20 N is applied to a body of mass 10 kg moving initially with a speed of 12 m s–1. How long does the body tak...
Which of the following is most correct about a balanced diet?
Which of the following instrument is used to measure heat radiation?
Relevant for Exams:
