Answer:
Proportional.
Step-by-step explanation:
Find the cross products. If they are same, then they are proportional.
Cross multiply,
1.2 * 4 .5 = 3*1.8
5.40 = 5.4
So, they are proportional.
Or
Multiply the numerator and denominator of 1.2/3 by 1.5
From this we come to know they are proportional
Or
1.2 : 3 :: 1.8 : 4.5
Product of means = 3*1.8 = 5.4
Product of extremes = 1.2*4.5 = 5.4
Product of means = product of extremes. So, they are proportional.
78
/ \
39 2
/ \
3 13
you cannot simplify the square root of 78.
Let
x--------> <span>the speed of the boat in mph
we know that
</span>going upstream the speed is x-7
<span>going downstream the speed is x+7
</span>
let the distance be d
<span>time to go upstream = d/(x-7) </span>
<span>time to go downstream = d/(x+7)
</span>
time going upstream is 3 times going downstream
so
<span>3d/(x+7) = d/(x-7) </span>
<span>divide by d </span>
<span>3/(x+7) = 1/(x-7) </span>
<span>3x-21 = x+7 </span>
<span>2x = 28 </span>
<span>x = 14
</span>
the answer is
<span>the speed of the boat in still water is 14 mph</span>
