Question

The mean of three numbers is 51. All the three number are different natural numbers . If two of them are 29 and 59, then find the third number​

Answer 1

Answer :

›»› The third number is 65.

Given :

• The mean of three numbers is 51.
• All the three number are different natural numbers.
• Two of them are 29 and 59.

To Find :

• The third number = ?

Solution :

Let us assume that, the third number is "x".

As it js given that, the mean of three numbers is 51.

→ 51 = (29 + 59 + x)/3

→ 51 * 3 = 29 + 59 + x

→ 153 = 29 + 59 + x

→ 153 = 88 + x

→ 153 - 88 = x

→ 65 = x

→ x = 65

Hence, the third number is 65.

Answer 2

Answer:

$\huge \bf \: given$

• Mean of three numbers - 51
• 1st number - 29
• 2nd number - 59

$\huge \sf \: to \: find$

3rd number

$\huge \sf \: solution$

$\small \fbox {first \: understand \: what \: is \: mean}$

Mean is the total of the number divided by the how many they are

$\bold {formula \: = \dfrac{total \: number}{number \: of \: the \: things \:} }$

Let the number be y

$\dfrac{29 + 59 + y}{51}$

$51 \times 3 = 29 + 59 + y$

$153 = 88 + y$

$153 - 88 = y$

$65 = y$

Verification

$\frac{29 + 59 + 65}{3} = 51$

$\frac{153}{3} = 51$

$51 = 51$

LHS = RHS

Hence proved