Explanation

Let the product of two real numbers = ab

One number =9

9a=72

A= 72/9

A=8

Explanation

Let the required two number be X and Y.

According to question

X+Y =40…………………………(i)

And the difference of two number is 4

X-Y=4……………………………(ii)

On solving both equation

Add equation (i) and (ii)

2X=44

So X= 44/2=22.

And put the value of X in equation (i)

We get

Y=22–4=18

So Y = 18.

Hence ratio of resultant number is

22/18=11:9.

Explanation

Volume of iron =π(R2−r2)×h

=π(42−32)×21

=722​×(16−9)×21

=462cm2

Weight =10008×462​kg=3.696kg

Explanation

Let the five consecutive even numbers be 2(x – 2), 2(x – 1), 2x, 2(x + 1) and 2(x + 2)

Their sum = 10x = 440

x = 44 => 2(x – 2) = 84

Second least number of the other set = 2(84) – 121 = 47

This set has its least number as 46.

Sum of the numbers of this set = 46 + 47 + 48 + 49 + 50

= 48 – 2 + 48 – 1 + 48 + 48 + 1 + 48 + 2 => 5(48) = 240

Explanation

Quantity of milk  =(60×32​) litres =40 litres

Quantity of water in it =(60−40) litres =20 litres

New ratio =1:2

Let the quantity of water to be added further be x litres

Then milk : water  =(20+x40​)

Now, (20+x40​)=21​

=> 20+x=80

=> x=60

Explanation

6 toffees --->                                     1 RS

Given profit % =                               20%

=> S.P of 6 toffees =                       1.2 RS

Now consider only S.P

1.2 re-->                                       6 toffee

1 re --->?                                     Toffee

6/1.2 =                                          5