First off, let's convert the percentages to decimal format, so our 77% turns to 77/100 or 0.77, and our 55% turns to 55/100 or 0.55 and so on
now, the sum of both salines, must add up to the 77% mixture, let's say is "y"
so, 11 + 4 = y, and whatever the concentration level is, must also sum up to the mixture's concentration of 77%
anyway thus

solve for "x"
Answer:
40000 and 12.5% respectively
Step-by-step explanation:
soln:
given,
cost price(c.p)=320000
selling price(s.p)=280000
loss(l),loss percentage(l%)=?
we know,
l=c.p-s.p
or,l=320000-280000
•°•l=40000
now,
l%=l/c.p*100%
or,l%=40000/320000*100%
•°•l%=12.5%
Each year the rent is multiplied by (1+0.055), so in 7 years, Natalie's rent will be
.. $900*1.055^7 = $1309.21
5.10÷85=$0.06<---
check your answer
85×0.06=$5.10