Answer:
Step-by-step explanation:
Present age of Barry = b
Present age of sister = s
Barry is 8 years older than his sister means if we subtract 8 from present age of Barry both will be of equal age
s=b-8 ............(1)
In 3 years means we have to add 3 in their present age
s+3=b+3
then
he will be twice as old as
2(s+3)=(b+3
2s+6=b+3
2s=b+3-6
2s=b-3...............(2)
Put the value of s from (1) to (2), we have
2(b-8)=b-3
2b-16=b-3
2b-b=-3+16
b=13
Put the value of b in (1)
s=13-8
s=5
Present age of Barry = b = 13
Present age of sister = s = 5
-1/4 will be ration because all fractions are rational
Answer:
100 million
Step-by-step explanation:
Let x=ab=ac, and y=bc, and z=ad.
Since the perimeter of the triangle abc is 36, you have:
Perimeter of abc = 36
ab + ac + bc = 36
x + x + y = 36
(eq. 1) 2x + y = 36
The triangle is isosceles (it has two sides with equal length: ab and ac). The line perpendicular to the third side (bc) from the opposite vertex (a), divides that third side into two equal halves: the point d is the middle point of bc. This is a property of isosceles triangles, which is easily shown by similarity.
Hence, we have that bd = dc = bc/2 = y/2 (remember we called bc = y).
The perimeter of the triangle abd is 30:
Permiter of abd = 30
ab + bd + ad = 30
x + y/2 + z =30
(eq. 2) 2x + y + 2z = 60
So, we have two equations on x, y and z:
(eq.1) 2x + y = 36
(eq.2) 2x + y + 2z = 60
Substitute 2x + y by 36 from (eq.1) in (eq.2):
(eq.2') 36 + 2z = 60
And solve for z:
36 + 2z = 60 => 2z = 60 - 36 => 2z = 24 => z = 12
The measure of ad is 12.
If you prefer a less algebraic reasoning:
- The perimeter of abd is half the perimeter of abc plus the length of ad (since you have "cut" the triangle abc in two halves to obtain the triangle abd).
- Then, ad is the difference between the perimeter of abd and half the perimeter of abc:
ad = 30 - (36/2) = 30 - 18 = 12
Rational numbers because not a whole numbe,r counting number or integer
