To solve that you're gonna have to multiply 2/3 by the reciprocal of 8/7 which is 7/8.
2/3 * 7/8 = (2 * 7)/(3 * 8)
14/24 reduces to 7/12 or .5833
2/3 / 8/7 flip the second fraction and multiply straight across
2/3 x 7/8 2 x 7 = 14
3 x 8 = 24 so you have 14/24 if you need to simplify, since both numerator and denominator are even so divide by 2. Which gives you 7/12
Hope this helps you :)
