2. 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 speeds of
walking and running.

The answer is below

Step-by-step explanation:

Speed is the ratio of distance covered to the time taken. Speed is given by the formula:

speed = distance / time.

Let us assume the spider walking speed is x and its running speed is y.

If the spider walks for 10 seconds and runs for 9  seconds, she travels 85m. distance = speed * time, hence:

Total distance = distance covered walking + distance covered running

10x + 9y = 85     (1)

Also if she walks for 30 seconds and  runs for 2 seconds, she travels 130m. Hence:

30x + 2y = 130   (2)

Solving equation 1 and 2 simultaneously by mutiplying equation 1 by 3 and subtracting equation 2 from the result:

25y = 125

y =5 m/s

Put  y = 5 in eqn. 2

30x + 2(5) = 130

30x = 120

x = 4 m/s

The spider walks at 4 m/s and runs at 5 m/s