The hospital can get 4.15 milligrams from these three companies.
A linear equation is one in which the highest power of any variable is not more than 1. A linear equation in 2 variables can be solved by substitution method, if we have two simultaneous equations.
Here, we know that
Company A's supply of medicine = 1.7 mg
also, company A's supply = 2( B's supply - C's supply)
⇒ 1.7 = 2( B - C)
⇒ 1.7 = 2B - 2C .... (1)
Moreover, we are given that
A's supply = C's supply + 0.9
⇒ 1.7 = C + 0.9
⇒ 1.7 - 0.9 = C
⇒ 0.8 = C
Now, substituting the value of C in (1), we get,
1.7 = 2B - 2(0.8)
1.7 = 2B - 1.6
1.7 + 1.6 = 2B
⇒ B = 3.3/2
B = 1.65
Thus, the total supply from all three companies is (1.7 + 1.65 + 0.8) = 4.15 mg
Learn more about Linear equations here-
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