essay 2-3 pages Cost & Estimating

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Lecture2-EstimatingMathematicsReview1.pdf

8/17/2020

1

Mathematics Review

LECTURE 2

Fractions, Ratios and Decimals

• Estimating may involve problems involving ratios, fractions or decimals.

• How do you go about solving these problems?

– Having a simplified version is key, i.e., resolving mixed fractions into improper fractions before calculations: 3 ¼ = 13/4

8/17/2020

2

Fractions, Ratios • Convert 41/7 into a mixed fraction

• Convert 8 1/9 into an improper fraction

• Convert 2.833333…into fraction

• Find the unknown values in (3-x)/5 –(x-2)/3 – 2x/5 = ½

• Solve: (1.9 x 0.032)

20 x 0.0038

• Solve for the unknown in √x = (2 +x)/3

• Two similar cylinders A and B have areas in the ratio of 9:16 respectively. Find the volume of B if A is 81 cubic yards.

• The ratio of the length of corresponding sides of two similar rectangular water tanks is 3:5. The volume of the smaller tank is 8.1 cubic yards. Calculate the volume of the larger tank

• The volume of a sphere is 8 cubic feet. What is its surface area

• A metal hemisphere of radius 12 ft is melted down and the liquid is used to construct a cone of base radius 6ft. Find the slant height of the cone.

Fractions, Ratios

• Solve the unknowns in the simultaneous equation

3x + 5y = 9 and 5x + 2y = 16

• A contractor makes an order for 500 bricks and 80 blocks and pays $8,450. In another order of 220bricks and 50blocks, he pays $4310. Find the cost of 1 block and 100 bricks

• A contractor mixed paints A, B, and C. The ratio of A:B = 2:4 and B:C = 5:7. What is the amount of C in a mixture of 200 in quantity.