Question

Crawling Crayfish!

Big Claw, the crayfish, challenged Flicker to a 60 em race. Since Big Claw is much
larger, he offered to give Flicker a 10 cm head start Flicker agreed and the race
began. After 5 seconds, Big Claw had crawled 6 cm and Flicker had crawled 4 cm.
If they continue at this rate, who do you predict will win the race? justify your
prediction
How many seconds have elapsed when Big Claw and Flicker are tied?

Answer 1

Answer: Crayfish, 25 s

Explanation:

Given

The length of race is 60 cm

Flicker gets a 10 cm head-start

Cray fish covers 6 cm in 5 s i.e. its speed is

`\Rightarrow (6)/(5)=1.2\ cm/s`

Flicker covers 4 cm in 5 s, its speed is

`\Rightarrow (4)/(5)=0.8\ cm/s`

Time taken by Cray fish to cover the race is

`\Rightarrow t_1=(60)/(1.2)\\\\\Rightarrow t_1=50\ s`

Time taken by flicker to cover race with 10 cm head start

`\Rightarrow t_2=(60-10)/(0.8)\\\\\Rightarrow t_2=62.5\ s`

Time taken by crayfish is less. Hence, crayfish wins the race

When they both covers the same distance, they tied momentarily i.e.

`\Rightarrow 1.2t=10+0.8t\\\Rightarrow 0.4t=10\\\\\Rightarrow t=(10)/(0.4)\\\\\Rightarrow t=25\ s`

After 25 s, they tied the race.