Question

A spider can walk at a certain speed and run at another speed. If she walks for 10 seconds and
runs for 9 seconds, she travels 85m. If she walks for 30 seconds and runs for 2 seconds she
travels 130m. Find her speed of walking and running.

Answer 1

Step-by-step explanation:

Let speed at which the spider runs be x m/s.

Let the speed at which the spider walks be y m/s.

1st case:-

Time for which the spider ran = 9s

Therefore, distance the spider covers by running = x×9 = 9xm

Time for which the spider walked = 10s

Distance the spider covers by walking = y×10 = 10ym

Total distance covered = 130m = (9x + 10y)m

2nd case:-

Time for which the spider ran = 2s

Therefore, distance the spider covers by running = x×2 = 2xm

Time for which the spider walked = 30s

Distance the spider covers by walking = y×30 = 30ym

Total distance covered = 85m = (2x + 30y)m

Therefore,

9x + 10y = 130  (×3, to make 30y)

2x + 30y = 85

To find x:-

27x + 30y = 390

2x   + 30y =   85

= 25x = 305

= x = 305/25 = 12 2/10 = 12.2 m/s or 122/10m/s

To find y:-

2 × 122/10 + 30y = 85       {Substituting the value of x, i.e. 122/10}

30y = 85 - 244/10 = 850 - 244/10 = 606/10

y = 606/10 / 30/1 = 606/10 × 1/30 = 606/300  = 2.02m/s

Therefore,

Running speed = 12.2 m/s

Walking speed = 2.02 m/s

Here is your answer. Hope it helps!

Answer 2

Answer:

walk=4m/s

run=5m/s

Step-by-step explanation:

we can do this by simultaneous equation.

please see the picture above