The tables show the cost of different numbers of t-shirts ordered at two different stores, store p and store q:

store p

number
of t-shirts cost (in $)
3 $18
6 $36
9 $54

store q

number
of t-shirts cost (in $)
2 $10
4 $20
8 $40

which of these explains which store has a better buy?
store q, because the ratio of the number to the cost is 1: 6 in store p and 1: 5 in store q
store q, because the ratio of the number to the cost is 6: 1 in store p and 5: 1 in store q
store p, because the ratio of the number to the cost is 3: 21 in store p and 2: 12 in store q
store p, because the ratio of the number to the cost is 21: 3 in store p and 12: 2 in store q

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116