Answer:
80 questions.
Step-by-step explanation:
-Let X be the number of problems solved on day 1.
-Questions solved on day 2 are:
[tex]=80\%\times x\\\\=0.8x[/tex]
We know that the total number of questions solved is 144:
[tex]x+0.8x=144\\\\1.8x=144\\\\x=80[/tex]
Hence, the number of questions solved on the first day is 80