Question

Ori needed at least $1.47 in postage to mail an envelope to his cousin overseas. If x represents the number of $0.44 cent stamps he has and y represents the number of $0.10 cent stamps he has, the inequality representing the number of stamps he can use to mail the envelope is 0.44x+0.10y≥1.47.

If Ori uses all 3 of the $0.44 cent stamps he has, what is the minimum number of $0.10 stamps he needs to use?

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Answer 1

If Ori uses all 3 of the $0.44 cent stamps, we first calculate the total value of the $0.44 stamps:

\[
\text{Total value of } 3 \text{ stamps} = 3 \times 0.44 = 1.32
\]

Next, we need to find the additional amount he needs in order to meet or exceed the minimum postage requirement of $1.47:

\[
\text{Additional amount needed} = 1.47 - 1.32 = 0.15
\]

Each $0.10 cent stamp adds $0.10 to the total. Let \(y\) be the number of $0.10 stamps needed. The equation we can set up is:

\[
0.10y \geq 0.15
\]

To find the minimum number of $0.10 stamps, we divide both sides by 0.10:

\[
y \geq \frac{0.15}{0.10} = 1.5
\]

Since \(y\) must be a whole number (you can't use a fraction of a stamp), we round up to the nearest whole number, which gives us:

\[
y \geq 2
\]

Therefore, the minimum number of $0.10 stamps Ori needs to use is **2**.