Ile kilogramów solanki 6-procentowej i ile kilogramów 9-procentowej należy zmieszać, aby otrzymać 9 kilogramów solanki 8-procentowej?

 solanka 6-procentowa=3 kg

solanka 9-procentowa = 6 kg

Step-by-step explanation:

Let solanka 6-procentowa=x kg

Let solanka 9-procentowa = y kg

So x+y=9  

=> x=9-y                           (1)

6%=0.06      9%=0.09    8%=0.08

So pure salt is 0.06*x +0.09*y= 9*0.08   (2)

Lets put 9-y instead x in (2)

0.06*(9-y) +0.09*y=0.72

0.54-0.06*y +0.09*y=0.72

0.03*y=0.18

y=6kg  =>  x=9-y => x=9-6=3 kg

answer

a,b, and d

explanation

a reflection angle is more than

but less than;

an angle that measures

is a reflex angle.(true)

an angle that measures less than

is acute.(true)

provided we are considering angles greater or equal to zero.

an acute angle lies in the range.

an obtuse angle is less than 180° but more than 90°

an angle that measures 300° is obtuse (false)

an angle that measures 65° is an acute angle.(true)