Answer:
Non-permissible value is 
Step-by-step explanation:
we are given equation as

we know that denominator can not be zero
so, we can set denominator =0
and then we can solve for y

we can subtract both sides by 3


So,
Non-permissible value is 
4 + .75m =10 i am not a math expert but i hope this helps
Let x be the time she ran and y be the time she walked
then distance ran = 25x and distance walked = 5y
so 15x + 5y = 42
and x + y = 4
* second equn. by -5:-
-5x - 5y = -20
add this to the first equn:0
10x = 22
x = 2.2
distance she ran = 2.2 * 15 = 33 km