Quantitative Aptitude - Arithmetic Ability Questions

The average marks obtained by a group of 10 students were 20. One student left the group as a result of which the average of the remaining students rose to 21. But another student joined, as a result of which the average marks of the group dropped a bit and became 20.6. What were the average marks obtained by the student who left and the one who joined?

What is the difference of the cube and square of the common root of (x2 – 8x + 15) = 0 and (y2 + 2y – 35) = 0?

In ΔPQR, S and T are points on side PQ and PR respectively. ST is parallel to QR. If S divides PQ in the ratio 1:5 and length of QR is 15 cm, find ST?

The ratio of two numbers is 5 : 6. If their product is 1470, then what is the sum of both the numbers?

If a3 + 3a2 + 9a = 1, then what is the value of a3 + (3/a)?

What is the simplified value of (cosec A – sin A)(sec A – cos A)(tan A + cot A)?

If the cost of 17 m of cloth is Rs. 77 5/7, find its cost per meter in Rs.?

What is the value of Sin 30° - Cosec 45°?