Quantitative Aptitude - Arithmetic Ability Questions

Three electronic devices make a beep after every 48 sec, 72 sec and 108 sec respectively. They beeped together at 10 a.m. The time when they will next make a beep together at the earliest is

The average of first 20 multiples of 12 is

The areas of two similar triangles ΔABC and ΔPQR are 36 sq cms and 9 sq cms respectively. If PQ = 4 cm then what is the length of AB (in cm)?

If a3 + b 3 = 35 and ab = 6, then what is the value of a + b?

If 3a – (3/a) – 3 = 0, then what is the value of a3 – (1/a3) + 2?

In a triangle PQR, ∠Q = 90°. If PQ = 12 cm and QR = 5 cm, then what is the radius (in cm) of the circum circle of the triangle?

If Sec θ = 13/12, then Cot θ = ?

Three numbers are in the ratio of 3:5:10 and their LCM is 630. Find their HCF.