A coffee blender mixes 2 types of coffee. Type A costs $13 per kg and type B costs $18 per kg. How many grams of each type of coffee must be blended so that 1 kg costs $15?

Answer 1

a,b means the weight of each .
13a+18b=(1)15
and a+b=1

multiply second equation by13 and subtract it from the first
13a+18b=(1)15
13a+13b=13
and then
5b=2 or b= .4kg, and then a=.6kg

Answer 2

can U explain where the one comes from