Carcass wrote:
0.025∗(7.5)∗48)5∗0.0024∗(3/4))
(A) 0.1
(B) 0.2
(C) 100
(D) 200
(E) 1,000
APPROACH #1: Use the on-screen calculator
APPROACH #2: Apply a useful property of fractions
Let's first convert
34 to
0.75, its decimal equivalent, to get:
0.025×7.5×485×0.0024×0.75=Key property: ABCDEF=AD×BE×CFStrategy: I'm going to use this property to split the original fraction into the product of 3 individual fractions.
There are a few different ways I can split up the fraction. For example, I could pair up 0.025 and 5 to get 0.025/5, but that seems like a pain to calculate.
Similarity, I could pair up 48 and 0.0024 to get 48/0.0024, but that also seems like a pain.
Instead, I'm going to use the fact that the answer choices are extremely spread apart in order to pair up values that I can easily approximate. So, we get:
0.0250.0024×7.50.75×485Let's evaluate (or approximate) each fraction individually.
0.0250.0024≈0.0250.0025≈(1000)(0.025)(1000)(0.0025)≈25025≈10 [multiplying numerator and denominator by 1000 resulted in a fraction with integer values only, which made it easier to calculate]7.50.75=(100)(7.5)(100)(0.75)=75075=10485≈505≈10Substitute values to get:
0.0250.0024×7.50.75×485≈10×10×10≈1000Answer: E