it should be used on the higher priced item to get a bigger discount.
So it should be used on the soccer ball
soccer ball: 22.50 * 0.30 = 6.75 discount
shin guards: 17.00 * 0.30 = 5.10 discount
6.75 is greater than 5.10
Disclaimer: Exchange rates vary almost on a constant basis, so it is best to always have an up-to-date chart from an online source. For the purposes of this problem, we don't have to worry about the rates changing.
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25 U.S Dollars = 20 Euros
25/20 U.S. Dollars = 20/20 Euros
1.25 U.S. Dollars = 1 Euro
<h3>The exchange rate is 1.25 U.S. Dollars per Euro</h3>
Saying "per Euro" is the same as saying "per 1 Euro". I divided both sides of the second equation by 20 so that I could turn the "20 Euros" into "1 Euro".
First you want to get it to y=mx+b. to do this you have to get the y by itself on one side. 2x-5y=7 you bring -5y over and get 2x=5y+7. Then bring the 7 over and get 2x-7=5y and finally get rid of the 5 by dividing both sides by it 2x-7/5 turns into 2/5x-7/5 and 5y becomes y. Y=2/5X-7/5. Next to get the slope of a line perpendicular to another you first flip the original slope (2/5x to 5/2x) and then reverse the sign (5/2x to -5/2x). and now you have Y=-5/2X+B. To get B you must put in what you know (X is 4, Y is 3) Get 3=-5/2(4)+B and solve.
3=-5/2(4)+B to 3=-10+B. bring -10 over and get 13=B and put that in. Finally you have Y=-5/2X+13.
(a) there are 8C2 = 28 ways of picking 2 girls from 8
And there are 21C4 = 5985 ways of picking 4 boys
Required number of ways for 2g / 4b = 28 * 5985 = 167,580
(b) at least 2 girls means combinations of 2g/4b , 3g,3b , 4g/2b , 5g 1b or
6 girls.
2g/4b = 167,580 ways
3g/3b = 8C3 * 21C3 = 56 * 1330 = 74,480
4g/2b = 8C4* 21C2 = 70 * 210 = 14,700
5g 1b = 8C5* 21 = 56*21 = 1176
6 girls = 8C6 = 28
adding these up we get the answer to (b) which is 257,964
