A rectangle has dimensions x by 2x. What is x if the perimeter of the rectangle is 48? Would it make this problem seem more relatable if we said it was a candy bar? Okay, it's a candy bar. Boom.
Answer
The perimeter is x + x + 2x + 2x = 6x. Solve the equation 6x = 48 to get x = 8. That's how much you'll be eating if all you do is nibble around the edges.
Example 2
The average of two numbers is 6. One number is 5 bigger than the other. What are the two numbers?
Answer
Let one unknown number be x. Then the other is x + 5. Solve the equation to find x = 3.5. The two numbers are 3.5 and 8.5.
Example 3
Dumbo the elephant likes to eat peanuts. What elephant doesn't? He eats all the peanuts the visitors to the zoo bring him. He made a New Year's Resolution to cut back, but they're always right there. If the visitors bring 100 peanuts and Dumbo eats them all over the space of four hours, how many peanuts per hour does Dumbo eat? Bonus question: how much liquid Maalox will he need to counteract the acid reflux brought on by his excessive peanut intake?
Answer
peanuts per hour
Example 4
Esmeralda wants to buy some exotic fish with blue speckles and long flowing fins. Mmm...delicious. The person at the fish store told Esmeralda that these particular fish need a lot of water in their tank in order for them to be comfortable: 1 gallon for the tank to start, plus an additional 2 gallons for each fish she throws in there. Esmeralda has a tank that holds 64 gallons of water. How many fish can Esmeralda's tank comfortably hold? Let's assume that Esmeralda does not actually intend to eat these guys, and therefore does have some amount of concern for their comfort. She's not an animal.
Answer
Solve the inequality 1 + 2x ≤ 64 (where x = number of fish) to get x ≤ 31.5. We don't want half a fish in the tank, as that will only pique the interest of the sharks, so 31 fish.
to find x = 3.5. The two numbers are 3.5 and 8.5.
peanuts per hour