Jessie saves $6 each week. In how many weeks will she have saved at least $50.

58.333 days

Explanation:
using "scale" can solve the problem
we know that Jessie take 7 days to save 6$
lets pretend "=" as "can get"
lets say:
7
d
y
=
6
$

7
d
y
⋅
k
=
6
$
⋅
k

by the way
6
$
⋅
k
is
50
$
, so k is
50
6

7
d
y
⋅
k
=
6
$
⋅
k

7
d
y
⋅
50
6
=
6
$
⋅
50
6

7
d
y
⋅
50
6
=
50
$

58.333
...
.
d
y
=
50
$
another way is to use a right triangle,
let the base has the width 7, each unit along the y-axis means "1 day"
let the height has the height 6, each unit along the x-axis means "1$"
now extend the height to 50 units, you will find your new big triangle has a base of 58.3 units
this is because the tangent of the angle is the same
graph{y = 6/7x [-28.13, 103.57, -3.1, 62.7]}