Posted by Ghiffari on Monday, October 24, 2011 at 8:34pm.
The numerator of a fraction is two less than its denominator. When both numerator and denominator are increased by 3, the fraction is incre
ased by 3/20. Find the original fraction. Pls include solution and workings thx :)
- Math - Reiny, Monday, October 24, 2011 at 9:20pm
first denominator -- x
first numerator ---- x-2
new denominator -- x+3
new numerator ---- x+1
(x-2)/x + 3/20 = (x+1)/(x+3)
times 20x(x+3) , the LCD
20(x+3)(x+1) + 3x(x+3) = 20x(x+1)
expanding and simplifying gave me
x^2 + 3x - 40 = 0
(x-5)(x+8) = 0
x = 5 or x=-8
if x=5, the original fraction was 3/5
if x=-8 the original fraction was -10/-8 or 5/4
check for 3/5 , new fraction would be 6/8 or 3/4
3/5 + 3/20 = 12/20 + 3/20 = 15/20 = 3/4
but for 5/4, new fraction would be 8/7
5/4 + 3/20 = 28/20 = 7/5 ≠ 8/7
BUT, if we take the unsimplified fraction -10/-8 , new fraction would be -7/-5 = 7/5
So the original fraction would be 3/5 for sure, but
also the unsimplified fraction -10/-8
Answer This Question
More Related Questions
- Mathematics - The numerator of a fraction is two less than its denominator. When...
- Maths - When the numerator and denominator of a fraction are each increased by 5...
- Algebra - When nine is added to both the numerator and the denominator of an ...
- MATHS - The numerator of a fraction is 4 less than twice the denominator. If ...
- math - The denominator of a fraction is 4 more than the numerator. If both the ...
- math - Solve this plxxx The numerator of a fraction is 2less than it's ...
- algebra - The denominator of a fraction is 4 less than the numerator .If the ...
- 8th grade math - The denominator of a fraction is 4 more than the numerator. If ...
- math - The numerator of a fractionis 5 less than twice the denominator. If the ...
- basic algebra - the numerator of a certain fraction is four less then the ...