Factor 4 cos2x-7 sin x cos X-2 sina x

Lady purchased 12 trinkets costing $0.30 each and 8 trinkets costing $0.65 each.

Step-by-step explanation:

A lady buys total number of trinkets = 20

Cost of each trinket is either $0.30 or $0.65.

Let the number of trinkets is x she purchased for $0.30 and y for $0.65

Then x + y = 20 --------(1)

Since she spends total amount = $8.80

Then the equation will be

0.30x + 0.65y = 8.80 ---------(2)

We replace x = (20 - y) from equation (1) to equation (2)

0.30(20 - y) + 0.65y = 8.80

6 - 0.30y + 0.65y = 8.80

0.35y + 6 = 8.80

0.35y = 8.80 - 6

0.35y = 2.80

y =

y = 8

Now we put y = 8 in equation (1)

x + 8 = 20

x = 20 - 8

x = 12

Therefore, lady purchased 12 trinkets costing $0.30 each and 8 trinkets costing $0.65 each.