An altitude is a line which passes through a vertex of a triangle, and is at right angles to the opposite side. A triangle has three altitudes.
I think the answer choice is in the tens place
The answer is <span>b.3x + 15 = 55 - x
</span>
x - Jill's present age
y - dad's present age
<span>In 5 years, Dad will be three times as old as his daughter Jill will be then:
y + 5 = 3(x + 5)
</span><span>The sum of their present ages is 50:
x + y = 50
We have the system of two equations now:
</span>y + 5 = 3(x + 5)
x + y = 50
Let's rearrange the second equation:
If: x + y = 50
Then: y = 50 - x
Now, substitute y from the second equation (y = 50 - x) into the first one:
y + 5 = 3(x + 5)
50 - x + 5 = 3(x + 5)
50 + 5 - x = 3*x + 3*5
55 - x = 3x + 15
Rearrange it a bit:
3x + 15 = 55 - x
Therefore, the correct choice is b.
