A = oz of the solution A
b = oz of the solution B
The scientist knows that solution A is 45% salt and solution B is 95% salt. She wants to obtain 80 ounces of a mixture that is 65% salt.
a + b = 80
0.45a + 0.95b = 0.65*80
by solving the above system of equations you'll find····
a = 48 oz
b = 32 oz
~I hope this helped~
If it doesn't make since, I can try to switch up the wording ^^
1. 10:37 and idk the second one
R=i/pt
R=1680/3000*8=1,680÷24,000
=0.07*100=7%
Lets Sean's age be x
Helen's age by y
x/y=3/5
x=3/5y
Second equation
2(x-2)=y-2
on solving u get Helen as 10 and Sean as 6