Each baker received 1.25 kilograms
12.60 / 7 = $ 1.80 per bottle
10.98 / 6 = $ 1.83 per bottle
18.10 / 10 = $ 1.81 per bottle
16.38 / 9 = $ 1.82 per bottle
best buy (cheapest) is : $ 12.60 for 7 bottles <==
T=D/R
You must isolate T so you divide R on both sides. This isolates T and gives you the answer.