A fraction has a value of 3/4. If 7 is added to the numerator, the resulting fraction is equal to the reciprocal of the original fraction. Find the original fraction.
Let the fraction be x/y. We're given two equations:
3(3y/4) + 21 = 4y
9y/4 + 21 = 4y
Multiply the equation by 4 on both sides to eliminate the denominator:
9y + 84 = 16y
To solve this equation for y, we type it in our math engine and we get:
y = 12
We then substitute y = 12 into equation 1 above:
x = 3 * 12/4
x = 36/4
x = 9
So our original fraction x/y = 9/12
Let the fraction be x/y. We're given two equations:
- x/y = 3/4
- (x + 7)/y = 4/3. (The reciprocal of 3/4 is found by 1/(3/4)
- 4x = 3y
- 3(x + 7) = 4y
- 4x = 3y
- 3x + 21 = 4y
- x = 3y/4
- 3x + 21 = 4y
3(3y/4) + 21 = 4y
9y/4 + 21 = 4y
Multiply the equation by 4 on both sides to eliminate the denominator:
9y + 84 = 16y
To solve this equation for y, we type it in our math engine and we get:
y = 12
We then substitute y = 12 into equation 1 above:
x = 3 * 12/4
x = 36/4
x = 9
So our original fraction x/y = 9/12