At-shirt shop charges $15 for an adult shirt and $12 for a youth shirt. the total charge for a shirt order was $489. which equation can be used to represent x, the number of adult shirts sold and y, the number of youth shirts sold? 12x + 15y = 489 27x + 15y = 489 15x + 12y = 489 15x + 3y = 489

 x, the number of adult shirts

 y, the number of youth shirts

$15 for an adult shirt and $12 for a youth shirt. The total charge for a shirt order was $489.

15x + 12y  = 489

Answer

15x + 12y = 489

The answer to this question is C : 15x + 12y = 489.

WHY?

It asks for the number of adult shirts (x represents how much was sold) and youth shirts (y represents how much was sold). $15 was for an adult shirt and $12 was for a youth shirt.

THAT'S WHY

15x + 12y = 489

^     +    ^  =   ^

adult + youth = total amount

Part a:

f(x) = 2.96(1.04)ˣ

the multiplier is given by 1.04 
multiplying  1.04 by 100, we have 104%
the increase is 104% - 100% = 4%

part b:

let's take the fuel price as a sequence
term 1 =3.04
term 2 = 3.22
term 3 = 3.41
term 4 = 3.61

the common ratio is given by

term 2/term 1 = 3.22/3.04 = 1.06
term 3/term 2 = 3.41 / 3.22 = 1.06
term 4/term 3 = 3.61 / 3.41 = 1.06

the value 1.06 represents the multiplier
multiply 1.06 by 100 to get the percentage form of 106%
the increase is   106% - 100% = 6%


fuel b gives the greater percentage change in price