If you add the digits in a two-digit number and multiply the sum by 7, you get the original number. If you reverse the digits in the two-digit number, the new number is 18 more than the sum of its two digits. What is the original number?
A. 42
B. 24
C. 64
D. 46
Е. 36

The answer is A. 42

Solution:

Let x= ones digit, y=tens digit

1st condition (original number) : 7(x+y)=10y + x

2nd condition (new number by reversing the digits): 18+x+y=10x+y

simplifying:

1st condition: 6x=3y

2nd condition: x=2

substituting x=2 to 6x=3y

y=4

42

Step-by-step explanation:

b. y = 4x - 2

step-by-step explanation:

to find a parallel equation to an equation, make sure both equations have the same slope but different y-intercepts.

y = 4x + 1

4 = slope

1 = y-intercept

y = 4x - 2

4 = slope

-2 = y-intercept

they both have the same slope but different y-intercepts, so, b. is the correct answer.

and to check your work, you can graph both equations. : )

answer: 10 turtles

step-by-step explanation: as turtles have four legs so 4.10=40 therefore birds are 4 which sue counted