On a circumference 120 cm long, there are a spider and an ant. If they move in a circle towards each other

| September 5, 2021 | education

On a circumference 120 cm long, there are a spider and an ant. If they move in a circle towards each other, they will meet in 12 seconds, and if one after another, then in 30 seconds. Find the speed of the spider and the speed of the ant.

1. The speed of the ant is equal to: Vm cm / sec;

2. The speed of the spider is equal to: Vn cm / sec;

3. Circumference: L = 120 cm;

4. They move towards each other with the total speed: Vc = (Vm + Vn) cm / sec;

5. The meeting time is equal to: Tb = 12 sec;

Vc = L / Tb = 120. 12 = 10 cm / sec;

6. One after another, the ant and the spider move with a difference speed: Vp = (Vm – Vn) cm /
sec;

7. Travel time before the meeting: Td = 30 sec;

Vp = L / Td = 120/30 = 4 cm / sec;

8. Determine the speeds Vm and Vn (adding and subtracting equations):

Vc = Vm + Vn = 10;

Vp = Vm – Vn = 4;

2 * Vm = 10 + 4 = 14;

Vm = 14/2 = 7 cm / sec;

2 * Vn = 10 – 4 = 6 cm / sec;

Vn = 6/2 = 3 cm / sec.

Answer: the speed of the ant is 7 cm / sec, the speed of the spider is 3 cm / sec.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.