Question 165328
Let x = final grade
.
The inequality looks like this:
70 <= (2/3)(48) + (1/3)x <= 79
70 <= (2)(16) + x/3 <= 79
70 <= 32 + x/3 <= 79
.
Looking at the left inequality first:
70 <= 32 + x/3 
210 <= 96 + x
114 <= x
.
Looking at the right inequality:
32 + x/3 <= 79
96 + x <= 237
x <= 141
.
Putting it all together:
114 <= x <= 141
This means Wendy has to score between 114 and 141 on her final exam.