+129852
For the first one, this is an inverse variation situation....as x decreases, y increases
However......it is not constant
For instance.....y increases 2.5 times from .04 to.1 and x decreases by 2.5 times from 310 to 124
And y increases 2 times from .1 to .2 while x decreases by 1/2 from 124 to 62
And y increases by 4 times from .2 to .8 and decreses by the same factor from 62 to 15.5
If we continued this apparent pattern......when x = 4, y = 15.5 / 4 * .8 = 3.1
For the second one, If Isabella can rake leaves in 7 hours, she must complete 1/7 of the job in one hour
And since Mark works 3 times as fast.....he can do 3(1/7) = 3/7 of the job in one hour
So....together....they can do 1/7 + 3/7 = 4/7 of the job in one hour
Flip this fraction over to find the total time to finish the job working together = 7/4 hrs =
1 + 3/4 hours = 1 hr, 45 min
