ECSTR Interview Questions, Process, and Tips

36

135 is wrong because from starting difference between 7 after that 9 after 11 ,13,17 and so on

Let the number be x.

So x-2 =15/x, or

x^2–2x-15=0, or

(x-5)(x+3)=0

Hence x = 5 or -3.

Check: When x=5, 5–2=3 which is 15/5=3.

When x=-3, -3–2=-5 which is 15/-3=-5.

The number is 5 or -3.

Suppose the lengthier arm of weighing pan is of x cm and other arm is y cm .Also let weight if each melon be m kg.
so applying equilibrium of torque principles ,we get
case 1:-
1x-8my=0
case 2:-
2mx-1y=0
using case 1 equation , we substitute value of x into case 2 equation;
16mmy-1y=0
(16mm-1)y=0
y is length of weighing arm and cannot be 0,
therefore ,
16mm-1 =0
16mm=1
mm=1/16
m= square root (1/16)
m=+-1/4
m is weight of melon and cant be negative.
Hence m, weight of one melon is 1/4 kg

120

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