+0

# Solving by Elimination

0
318
1

A hovercraft travels over flat land at 40km/h and over rough water at 10km/h. if it takes 5.75h to travel 185km, then how far did it travel over

a) land                                        b) water

Jun 24, 2017

#1
+1

A hovercraft travels over flat land at 40km/h and over rough water at 10km/h. if it takes 5.75h to travel 185km, then how far did it travel over

a) land                                        b) water

Distance =Speed x Time

Let the distance it travelled over land = L, then:

The distance it travelled over water =185 - L

L/40 + [185-L]/10 = 5.75, solve for L

L = 170 Km - the distance it travelled over land.

185 - 170 = 15 Km - the distance it travelled over water.

P.S. You could construct two simultaneous equations and solve them by elimination. But it is not necessary in this problem since we can easily solve it with one linear equation as I have shown above. If you wish to have two simultaneous equations, they can be written like this:

L + W = 185

L/40 + W/10 =5.75, solve for L, W

If you try to solve them, you will see that you will  get the same answer as I got above:

L =170 km, and

W =15 Km.

Jun 24, 2017
edited by Guest  Jun 24, 2017

#1
+1

A hovercraft travels over flat land at 40km/h and over rough water at 10km/h. if it takes 5.75h to travel 185km, then how far did it travel over

a) land                                        b) water

Distance =Speed x Time

Let the distance it travelled over land = L, then:

The distance it travelled over water =185 - L

L/40 + [185-L]/10 = 5.75, solve for L

L = 170 Km - the distance it travelled over land.

185 - 170 = 15 Km - the distance it travelled over water.

P.S. You could construct two simultaneous equations and solve them by elimination. But it is not necessary in this problem since we can easily solve it with one linear equation as I have shown above. If you wish to have two simultaneous equations, they can be written like this:

L + W = 185

L/40 + W/10 =5.75, solve for L, W

If you try to solve them, you will see that you will  get the same answer as I got above:

L =170 km, and

W =15 Km.

Guest Jun 24, 2017
edited by Guest  Jun 24, 2017