I believe the answer is A. 40.
Answer:
680
Step-by-step explanation:
Ratio of red to white 4 : 7
Number of white = 280
White + red buttons = x
7x / 11 = 280
7x = 280 * 11
7x = 3080
x = 3080 / 7
x = 440
Number of red buttons 440 - 280 = 160
Number of red bottons ;
Blue + red buttons = x
3 : 2 ; blue : red
3 + 2 = 5 ;
2x / 5 = 160
2x = 160 * 5
2x = 800
x = 800 / 2
x = 400
Number of Blue buttons :
400 - 160 = 240
Total :
White + red + blue
280 + 160 + 240 = 680 buttons
If each week the tank decreased by 3 inches, in 2 weeks it would be 6 in, 3 weeks is 9 in, 4 weeks would be 12 in, and 5 weeks would be 15 in.
