Answer:
t3 = 8, t5 = 14
Step-by-step explanation:
t3 = 2 + (3-1) × 3
t3 = 2 + (2) × 3
t3 = 2 + 6
t3 = 8
t5 = 2 + (5-1) × 3
t5 = 2 + (4) × 3
t5 = 2 + 12
t5 = 14
In this item, it is not given that there has to be specific arrangement or order as to how the questions are going to be answered. Hence, the concept that can be used in order to answer this item is the concept of combination which states that,
nCr = n! / (r!)(n - r)!
This is read as "combination of n taken r". In this item, n = 10 and r = 4. Substituting the known vaues to the equation,
10C4 = (10!) / (4!)(10 - 4)!
10C4 = 210
Therefore, the number of which is which the questions can be answered is 210.
The key calculation in this problem is figuring out <em>how many times 80 goes into 1,000,000</em>. I'll build up in steps here.
80 x 5 = 400. This gives us a building block on our way to 1,000,000. From here, we can go further and say that 400 x 5 = 2,000; that 2,000 x 5 = 10,000; and finally that 10,000 x 100 = 1,000,000. Altogether, starting from 80, that's
80 x 5 x 5 x 5 x 100 = 80 x 25 x 500 = <em>80 x 12,500</em>
So, since 80 goes into one million 12,500 times, it takes 12,500 minutes for the animal's heart to beat that 1,000,000 times.
