Help asap please math if you put in a random answer you will be reported. Tysm! (Do not show your work just put in the RIGHT answer!) TYSm! :D

6. 80 or B

7. 188 or C

Step-by-step explanation:

6.

c=a2+b2=42+42≈5.65685

V=1 /4h﹣a4+2(ab)2+2(ac)2﹣b4+2(bc)2﹣c4=1 /4·10·﹣44+2·(4·5.66)2+2·(4·4)2﹣5.664+2·(5.66·4)2﹣44

≈80

7.

A=2(wl+hl+hw)=2·(2.7·4.8+10.8·4.8+10.8·2.7)

≈187.92 rounded to 188

step-by-step explanation:

30% of $420 is 0.30($420) = $126 and $420 + $126 = $546.

or, 130% of $420 is 1.3($420) = $546.

notice that this is not the $600 original list price with which we started.

why doesn't this work?

the method does not work because 30% of $420 is not the same amount as the 30% of $600. it may seem obvious when stated this way, but it is a very common error made on problems of this type. we cannot just use the same percent and get back to the original amount because we are taking that percent of a different value.

to work problems of this type correctly, it is generally best to write an equation for the situation and then solve.

example: since (100% – 30%)(original price) = (sale price)

70% of the   (original price) is $420.

0.7x   = 420

equation image indicator

x = 600

the original cost was $600.

we may also solve this problem using the two-step method. working the problem in two steps requires us to use more algebra skills. we have to know that x = 1x (identity property of multiplicationtext annotation indicator) and that 1x – 0.3x = 0.7x (subtracting like terms). then we solve the problem as follows:

(original price) – 30%(original price) = sale price

x – 0.3x = 420

0.7x = $420

equation image indicator

x = 600

the original cost was $600.  

note that with both of the above methods we do obtain the correct original amount.

example: after a 5% pay raise, hermione is earning $22,680 per year. what was she earning before the pay raise?

105% of (original salary) = current salary

1.05x = 22,680

equation image indicator

x = 21,600

hermione earned $21,600 per year before the pay raise.

this is an example so maybe you will get how to at least do it!