If SQRT(x+15) + SQRT(x)=15 then find the value of x.

Given x is a real number, If SQRT(x+15) + SQRT(x)=15 then find the value of x.

Solution -

It infers sqrt(x+15)=15-sqrt(x) square both sides
x+15=225+x-30*sqrt(x) or
sqrt(x)=7 or x=49 substitute in the statement o.k.

The ratio between the present ages of Pawan and Rohan is 5:7...............What is the sum of Pawan

The ratio between the present ages of Pawan and Rohan is 5:7 respectively.
If the difference between Rohan’s current age and Pawan’s age after 6 years is 2.
What is the sum of Pawan & Rohan current age?

Solution -

R/P=5/7
R-(P+6)=2 OR R-P=8 Substitute above relation
R-5R/7=8 or 2R/7= 8 giving R=28 and P=20

How many 3 digit numbers can be formed from digits 2, 3, 5, 6, 7 & 0, which are divisible by 5 a

How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 0, which are divisible by 5 and none of the digits is repeated?

Solution -

Looks 36. Ending with 0 we have to select two others from 5 which means 5P2=20. Similarly ending with 5 we have another 20 of which 4 starting with zero must be excluded. Hence 20+16=36

Simplify 9^2^-1^3^4^5

Simplify 9^2^-1^3^4^5




Solution -

1^3^4^5 = 1
9^2^(-1) = 9^(1/2) = sqrt of 9 = 3.

How much worth chocolate should he buy so that he can accommodate it in Rs 100 ?

Rohit went to buy some expensive, foreign chocolates. He only had Rs 100 with him. When he reached the shop, he got to know that on those chocolates, there was a 15% import duty and 5% VAT.

How much worth chocolate should he buy so that he can accommodate it in Rs 100 ?

Solution -

If the VAT is added on the base price + Import Duty then

He would be able to buy chocolates worth Rs. 82.816

82.816 + Import Duty @ 15% Rs.12.422 = 95.238

Add 5% VAT on 95.238
Rs. 4.762

95.238 + 4.762 = 100

A sum is increased to 40% in 8 years at SI. What will be the compound interest of Rs. 1600 after 3 y

There is 40% increase in an amount in 8 years at simple interest. What will be the compound interest of Rs. 1,600 after 3 years at the same rate?

Solution -

Simple interest comes 40/8=5 %. Amount from principal of 1600 at 5% for three years becomes 1600*1.05^3=1852.20. Therefore compound interest comes Rs. 252.20

The difference between simple interest and compound interest on a sum for 2 years at 8% is Rs.16...

The difference between simple interest and compound interest on a sum for 2 years at 8%, when the interest is compounded annually is Rs.16. If the interest were compounded half yearly, then what would be the difference between simple interest and compound interest for the same sum in 2 years?

Solution -

the difference between the compound interest and simple interest for 2 yearsmay be arrived in the form PxRXR/10000.
R=8,solving get P=2500
Simple interest for the amount=400
comp interest =416
comp interest half-yearly =424.65
hence difference =24.65