math problem help

Question

A farmer has several packages of fertilizer for his new grain crop. The old packages contain

50

pounds of​ long-term-growth supplement and

60

pounds of weed killer. The new packages contain

65

pounds of​ long-term-growth supplement and

45

pounds of weed killer. Using past​ experience, the farmer estimates that he needs

3700

pounds of​ long-term-growth supplement and

3450

pounds of weed killer for the fields. How many old packages of fertilizer and how many new packages of fertilizer should he​ use?

Answer 1

50/60 old ratio= 5/6

65/45 new ratio = 13/9

need 3700/3450 ratio = 370/345 = 72/69 = combined ratio

5x/6 +(x-7150)(13/9)== 7150(3700/3450)

solve for x = about 4352 pounds of old

7150-x = about 2798 pounds of new

mixed to get

7150 pounds of 3700/3450 ratio