Answer:
770 high-quality songs were downloaded
Step-by-step explanation:
A web music store offerst two versions:
There were 1290 for a total download size of 4403MB.
According to the information above, we have the following system of equations:
A + B =1290
2.1A + 4.3B = 4403
Where 'A' referst to the number of Standard songs and 'B' refers to the number of High Quality songs.
Solving the sistem of equations we get that:
A + B =1290 ⇒ A = 1290 - B
2.1A + 4.3B = 4403 ⇒ 2.1(1290 - B) + 4.3B = 4403
⇒ 2709 - 2.1B + 4.3B = 4403 ⇒ 2.2B = 1694 ⇒ B=770
Now, let's find the value of 'A':
A + B =1290 ⇒ A = 1290 - 770 ⇒ A = 520.
Therefore, 770 high-quality songs were downloaded.