Answer:
42
Step-by-step explanation:
a = 2, b = 5, and c = 1
- a*(4b + c²) = ⇒ plug in values
- 2*(4*5 + 1²) = ⇒ solving exponents
- 2*(20 + 1) = ⇒ parenthesis
- 2*21 = ⇒ multiplication
- 42 ⇒ answer
First, we determine the speed of the ferry by dividing the distance by the time it took to cover that certain distance.
speed = (1/6) / (3/7)
speed = 7/18
Then, the distance it will travel for an hour is calculated through the procedure below.
distance = (7/18hour) x (1 hour)
distance = 7/18
Therefore, after an hour, the ferry will be able to travel 7/18 of the distance between two ports.
5. The 5th figure will have 30 tiles.
6. The 6th figure will have 42 tiles.
7. The pattern is non-linear (quadratic).
8. The 20th figure can be made with 420 tiles.
_____
The Nth figure is made with n*(n+1) tiles. To answer question 8, you must solve
.. n(n +1) = 420
.. n^2 +n -420 = 0
.. (n +21)(n -20) = 0
.. n = 20 or -21 . . . . the negative solution is extraneous
