Answer:
7/17
Step-by-step explanation:
For easier calculation , let us represent the total number of stereo produced with a figure that can easily be divide into 3 .
Let us use 21 as the total number of stereo produced.
Basic stereo = 2/3 * 21 = 14
Deluxe stereo = (1- 2/3)*21 = 7
Now , if it takes 7/5 as many hours to produce a deluxe stereo to produce a basic stereo.
Let us assume that it took 2 hours to produce each deluxe stereo, then each basic stereo was produced in 7/5 *2 = 14/10.
Total hours used to produce basic stereo = 14 *14/10 = 19.6. approximately 20
Total hours used to produce deluxe stereo = 2*7 = 14
Total number of hours for all stereo = 20+14 = 34
fraction of delute stereo hours to total stereo hours = 14 / 34 = 7/17