5.
goal is at least 180
goal is greater than or equal to 180
goal≥180
how much they raise=amount per keychain times number of keychains
how much they raise=2.25 times k
so
2.25k≥180
solve
divide both sides by 2.25
k≥80
fourth option (D)
6.
average, so divide all scores by 3, so (83+91+n)/3
between 85 and 90 so
greater than 85 and less than 90
85≤(83+91+n)/3≤90
now solve
times everybody by 3
255≤83+91+n≤270
255≤174+n≤270
minus 174 from everybody
81≤n≤96
first one (A)
so
5. first one
6. last one