#13 omar is 3 times as old as jason, henry is 5 years older than jason. if their total age is 80 years old, how much older is omar than henry?
 
#14 mrs anderson had twice as many chickens as ducks. she sold 272 chickens and 16 ducks. she then had half as many chickens as ducks. how many chickens did she have in the beginning?
 
#15 mrs. ortega paid $188 for some jeans and t-shirts. a pair of jeans costs $26, and a t-shirt was $16 cheaper than a pair of jeans. if mrs ortega bought 3 pairs of jeans, how many t-shirts did she buy?
show explanation

13. Let's say Jason's age is x, Omar's age is y and Henry's age is z. Then we have:y = 3x (Omar is three times as old as Jason) z = x + 5 (Henry is five years older than Jason) x + y + z = 80 (Their total age is 80) Now replace y and z in the last equation with the two other equations and you get: x + 3x + (x + 5)= 80 Calculate brackets: x + 3x + x + 5 = 80 Move 5 over and add up the x:  5x = 75 x = 75/5 = 15 So Jason is 15. Now we put x = 15 into the other equations and we get: Omar's age: y = 3*15 = 45 Henry's age: z = 15 + 5 = 20 So Omar is 25 years older than Henry.

14.

Let c = chickens and d = ducks, then:

c = 2d

c - 272 = 1/2 (d - 16)

We can rewrite the expression in terms of one variable, d:

2d - 272 = 1/2 (d - 16)

2d - 272 = 1/2d - 8

3/2d = 264

d = 176

c = 2 * 176 = 352

She had 352 chickens in the beginning.

15.

11-shirts