Answer: 40 seconds. This is the equation graphed
<span><span>let x = cows last year
</span>
</span><span><span>let y = bulls last year
</span>
</span><span><span>x + y = last years total
</span>
</span><span><span>0.9x + 1.5y = 660 (this year's total)
</span>
<span>1.1(x+y) = 660 </span>= </span><span>1.1x + 1.1y = 660
</span><span>
</span><span><span>so:
</span>
</span><span><span>0.9x + 1.5y = 1.1x + 1.1y
</span>
</span><span><span>subtract 0.9x from each side:
</span>
</span><span><span>1.5y = 0.2x + 1.1y
</span>
</span><span><span>subtract 1.1y from each side
</span>
</span><span><span>0.4y = 0.2x
</span>
</span><span><span>to make x 1 multiply both sides by 5
</span>
</span><span><span>2y = x
</span>
</span><span><span>substitute for x in one of the original problems:
</span>
since they had 660 this year and that number is 10%
higher than last year, then we had 600 total last year. </span>
<span><span>So:
</span>
</span><span><span>600 = x + y
</span>
</span><span><span>substitute into that one with the 2y = x
</span>
</span><span><span>600 = 2y + y
</span>
</span><span><span>600 = 3y
</span>
</span><span><span>200 = y
</span>
</span><span><span>then 600 - y = x
</span>
</span><span><span>so 600 - 200 = x
</span>
400 = x</span>
<span> So you had 400 cows and 200 bulls last year</span>
They earned 1800 in the five hours. First you need to multiply 12 by 10 and the 12 by 20 which will equal to 360 all together and then you need to multiply that by 5 which equals 1800.
Answer: 1/2
Step-by-step explanation:
