A store sells almonds for $16 per kilo and peanuts for $6 per kilo. If it sells 20 kilos of mixed nuts for $13 per kilo, how many kilos of almonds are in the mixed nuts?
Almonds = x
Peanut = y
x +y = 20
16x + 6y = 20(13)
x + y = 20
16x + 6y= 260
Substitute
y = 20-x
16x + 6(20-x) = 260
16x + 120 -6x = 260
10x +120 = 260
10x + 120-120 = 260-120
10x = 140
x = 14
y = 20-x
y = 20-14
y = 6
Almonds 14 kilos