A digit is a number in one of the places, so for example the number 54 has two digits; a tens place digit (5) and a ones place digit (4).
Say the mystery number is a two digit number = xy
* that's not x times y but two side by side digits.
Info given:
<span>the sum of the digits of a two-digit number is 6
x + y = 6 </span>
<span>if the digits are reversed, yx the difference between the new number and the original number is 18.
**To obtain the number from digits you must multiply by the place and add the digits up. (Example: 54 = 10(5) + 1(4))
Original number = 10x + y
Reversed/New number = 10y + x
Difference:
10y + x - (10x + y) = 18
9y - 9x = 18
9(y - x) = 18
y - x = 18/9
y - x = 2
Now we have two equations in two variables
</span>y - x = 2
<span>x + y = 6
Re-write one in terms of one variable for substitution.
y = 2 + x
sub in to the other equation to combine them.
x + (2 + x) = 6
2x + 2 = 6
2x = 6 - 2
2x = 4
x = 2
That's the tens digit for the original number. Plug this value into either of the equations to obtain y, the ones digit.
2 + y = 6
y = 4
number "xy" = 24
</span>
Area of square = 8^2 = 64
Area of circle = pi x r^2 = 3.1415 x 4^2 = 50.27
64 - 50.27 = 13.73
answer
area inside square but outside circle = 13.7 in^2 (it's C.)
11.2, 12.5, 12.5, 13.23, 13.23, 14.5, 15.6, 15.75
It's 13.23
Answer: 28/32 but converted its 7/8. My work is kinda messy sorry. But this is my work.
The answer would be "B", 246 m2.
