1. Simultaneous and linear equations

A rower travels upstream at 6 km per hour and back to the starting place at 10 km per hour. The total journey takes 48 minutes. How far upstream did the rower go?

A man travels from A to B at 4km/h and then from B and A at 6 km/h. The total journey takes 45 minutes. Find the distance travelled.

2. Originally Posted by delicate_tears
A rower travels upstream at 6 km per hour and back to the starting place at 10 km per hour. The total journey takes 48 minutes. How far upstream did the rower go?
...
If
v is the speed
d is the distance
t is the time
then you are supposed to know that $v=\frac dt$

Let x be the distance and y be the time rowing upstream then you have
total time t = 0.8 h = 48 min
rowing upstream: y
rowing downstream 0.8 h - y

$\left| \begin{array}{r}6=\frac xy\\10 = \frac x{0.8-y}\end{array}\right.$ .... Multiply by the denominators: $\left| \begin{array}{r}6y= x\\10(0.8-y) = x \end {array} \right.$

Substitute x by 6y:

$8-10y = 6y~\iff~y=\frac12$

The rower needs half an hour to row upstream by a speed of 6 $\frac{km}{h}$ that means the distance upstream is 3 km.

3. Originally Posted by delicate_tears
...

A man travels from A to B at 4km/h and then from B and A at 6 km/h. The total journey takes 45 minutes. Find the distance travelled.
Let d be the distance between A and B.

From $v=\frac dt$ you get: $t=\frac dv$. With your problem:

$\frac d4 + \frac d6 = \frac34$ .......... Multiply by 24:

$6d + 4d = 18~\iff~d=1.8$

The total distance is therefore 3.6 km

,

,

,

,

a man travels 10km in 50mm if he runs for 8km and walks for 2km.if he runs 4km and walks 6km,hrs time is 1h 15mins.find his running and walking speed under maths using simultaneous equations

Click on a term to search for related topics.