Zayden has a total of 20 bills in his wallet. Also, his wallet only contains $50 and $100 bills. If the numbers of $50 and $100 bills are interchanged, the total amount of money in Zayden’s wallet would be $500 more than it originally was. Find the original amount of money in his wallet. $

Step-by-step explanation:

x = number of $50 bills

y = number of $100 bills

x + y = 20

50x + 100y + 500 = 100x + 50y

50y + 500 = 50x

y + 10 = x

now we use that in the first equation :

y + 10 + y = 20

2y = 10

y = 5

x = y + 10 = 5 + 10 = 15

so, he has 15 $50 bills and 5 $100 bills = $750 + $500 = $1250 in his wallet

hello!

to begin with, we're given that on earth, a rock weighs 20 pounds, and while on jupiter, that same rock weighs 42 pounds. now, we're trying to find the weight of a rock that weighs 10.5 pounds on earth, on jupiter.

to solve this, first, set up a proportion, cross-multiply, and solve it algebraically.

setting up the proportion is the hardest and the most confusing part of the problem, but it's simple.

if on earth, the rock weighs 20 lbs, and on jupiter it weighs 42 lbs, our first part of our proportion is 20/42 lbs. the second part has to be equal to each other. this means that 10.5 has to be on the numerator of the fraction, and x, the value we're trying to find, has to be on the denominator. remember that the rock weighs 10.5 lbs on earth, and we're trying to find the weight of it on jupiter (which is x).

20/42 = 10.5/x

next, you would cross-multiply.

20x = 42(10.5)

20x = 441

now, solve it algebraically by using division.

x = 22.05 lbs

this can be rounded to 22.1 lbs.

therefore, the weight of the rock on jupiter is 22.1 lbs, the fourth choice.