Bruce wants to make 50 ml of an alcohol solution with a 12% concentration. He has a 10% alcohol solution and a 15% alcohol solution.
Which equation can Bruce use to determine how much of the 10% alcohol solution he should use?
0.10.x + 0.15(50 - x) = 50+ 0.12

0.1x+0.15(50-x)= 50*0.12

Step-by-step explanation:

50 ml of 12% solution has 50*0.12 ml of alcohol

x ml of 10% solution has x*0.1 ml of alcohol

(50-x) ml of 15% solution has (50-x)*0.15 ml of alcohol

The equation to solve is:

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."