Home / Assignment Help / Pamela can swim under water for 51 seconds without a breath. Lucy can swim 3/5 minute and kady 8 minute. Who can stay underwater the longest?

Pamela can swim under water for 51 seconds without a breath. Lucy can swim 3/5 minute and kady 8 minute. Who can stay underwater the longest?

So hmmm we’ll start off by using the decimal format for the percentage, thus 15% is just 15/100 or 0.15 and 7% is just 7/100 or 0.07 and so on

notice, the concentration of alcohol in the 15% is, well, 0.15 :), so for a quantity of whatever, it’d be 0.15whatever

anyway, for water… water has no alcohol whatsoever, so the concentration is 0%, or 0/100 which is 0.00 or a flat 0

bf begin{array}{lccclll}
&amount&concentration&
begin{array}{llll}
concentrated\
amount
end{array}\
&-----&-------&-------\
textit{15% sol'n}&14&0.15&14(0.15)\
water&x&0.00&0x\
-----&-----&-------&-------\
textit{7% mixture}&y&0.07&0.07y
end{array}

we know that we’ll be adding “x” water with the 14mL to get “y”, thus 14+x = y

and the concentrated quantities will also add up to -> 14(0.15) = 2.1, thus
2.1 + 0x = 0.07y

bf begin{cases}
14+x=boxed{y}\
2.1+0x=0.07y\
----------\
2.1=0.07left( boxed{14+x} right)
end{cases}

solve for “x”.

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