Question

A tortoise makes a journey in two parts; it can either walk at 4cm/s or crawl at 3cm/s. If the tortoise walks the first part and crawls the second, it takes 110seconds. If it crawls the first part and walks the second, it takes 100 seconds. Find the lengths of the parts of the journey.

Answer 1

Solution:
Let x cm - walk
Let y cm - crawl

x/4 + y/3 = 110

3x+4y /12= 110

3x+4y = 1320... Eq.1

x/3 + y/4 = 100

4x+3y / 12 = 100

4x+3y = 1200...Eq.2

Let multiply equation 1 by -4
Let multiply equation 2 by 3

-12x-16y= -5280
12x+9y = 3600

Add the two equations

-7y = -5280+3600

-7y = -1680

y = -1680/-7

y = 240 cm crawl

Substitute the value of y in equation 1

3x+4y=12*110

3x+960=1320

3x=1320-960

3x=360

x = 120 cm walking

Hope this would help