Question

The sum of the digits of a two digit number is 7. If the number formed by reversing the digits is less than the original number by 27, find the original number. The sum of three consecutive odd numbers is 51. Find the numbers.

Answer 1

Answer:

sum of three consecutive odd number

x+(x+2)+(x+4)=51

3x+6=51

3x=45

x=15

the numbers are 15,17,19

Step-by-step explanation:

Answers

Let the units place be x

then the tens digit be 7 - x

number formed by these digits = 10 x t's digit+u's digit

=> 10(7-x)+x

70 x -10 x +x

70 x -9x

when the digits are interchanged than,

t's digit= x

u's digit = 7-x

the new no. formed = 10x + 7-x

= 9 x +7

given that the no. exceeds by 27

new no. - given no.

9x +7 - (70-9x)=27

9 x + 7 - 70 + 9x =27

18x -63= 27

18 x = 63+27

18 x= 90

x = 90/18

=5

the no. = 70- 9x

=> 70-45

=> 25 ans

verify : 2+5 = 7

Answer 2

Answer:

Let the original number be 10(X)+7-x

=10x-x+7

=9x+7

we know that

9x+7-27=10(7-x)+X

9x-20=70-10x+x

9x-20=70-9x

9x+9x=70+20

18x=90

X=90÷18

X=5

therefore the original number is 52