Answer:
He answered 20 questions correctly.
Step-by-step explanation:
25×.8(80%) = 20.
Ben wanted to take some money from his Friends to build his family a home. He said that he would give the money back after 12 months. So he would give 1500$ a month. How much money did he borrow?
1500*12=x
Matilda got also money, she told Ben, I got x $ from my dad and y $ from mom. all they gave me was 5000$. If I gave mom Half of the moneys I got from her than I would have 3000$ left to pay. How much did she borrow from her parents?
x+y=5000
and
x+y/2=3000
so x=5000-y
and
5000-y+y/2=3000
so
x=5000-y
and
y=4000
so x=1000 and y=4000
This is an arithmetic series, so we know, that:
Sum = (First term + Last term) * Number of terms /2
Here we have:
First term = 33
Last term = 104
Number of terms = 104 - 33 + 1 = 72
and
3x+7=22
Subtract 7 to both sides
3x=15
Divide by 3
x=5
