Can u help me wth math

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

Me asap the graph shows the relationship between the price of frozen yogurt and the number of ounces of frozen yogurt sold at different stores and restaurants according to the line of best fit about how many ounces of frozen yogurt can someone purchase for $5? 1 cost of frozen yogurt 1.5 2 13 15.5 cost (5) no 2 4 6 8 10 12 14 16 18 20 size (oz)