Question

suna tha brainly mein sab talented log honge
par yaha toh koi mera maths ka simple questions ko solve nhi kar paa rha .. XD


I've maths exam today.
Try to solve it...
​

Answer 1

Question:-

Five times the sum of the digits of a two digit number is 9 less than the number formed by reversing it's digits. If four times the digit at ones place is equal to half of the place value of the digits at tens place. Find the number.

Given:-

• Five times the sum of the digits of a two digit number is 9 less than the number formed by reversing it's digit.
• Four times the digit at ones place is equal to half of the place value of the digit at once place.

To Find:-

• The number.

Assumption:-

• Let the digit at one's place be x
• and ten's place be y

Solution:-

As we have assumed the digit at one's place and ten's place to be x and y respectively, we can write:-

Original number = 10x + y

Number formed after reversing the digits = 10y + x

ATQ,

5 times the sum of digits of the digits of a two digit number is 5 times less than the number formed by reversing it's digits.

= 5(x + y) = (10y + x) - 9

⇒5x + 5y = 10y + x - 9

⇒5x - x + 5y - 10y = -9

⇒ 4x - 5y = -9 ⟶ (i)

Also,

4 times the digit at one's place is equal to half of the place value of one's digit.

= 4 × y = 1/2 × 10x

⇒4y = 5x

⇒ y = 5x/4 ⟶ (ii)

Putting the value of y from equation (ii) in equation (i)

= 4x - 5y = -9

⇒ 4x - 5 × 5x/4 = -9

⇒ 4x - 25x/4 = -9

⇒ (16x - 25x)/4 = -9

⇒ 16x - 25x = -9 × 4

⇒ 16x - 25x = -36

⇒ -9x = -36

⇒ x = -36/-9

⇒ x = 4

Putting the value of x in equation (ii)

= y = 5x/4

⇒ y = (5 × 4)/4

⇒ y = 5

Therefore we got the value of:-

• x = 4
• y = 5

∴ The number is as follows:-

10x + y

= 10 × 4 + 5

= 40 + 5

= 45

∴ The original number is 45.

________________________________