ANSWER THE FOLLOWING QUESTIONS AND SHOW ALL WORK. And use proper significant fig

Question

ANSWER THE FOLLOWING QUESTIONS AND SHOW ALL WORK. And use proper significant figure
1.) a cyclist rides an average speed of 18 miles per hour. if she wants to bike 212 km, how long (in hours) must she ride ?

2.) total US farmland occupies 954 million acres (1 acre = 43560 ft^2) how many square miles is this ?
Total land area is 3.537 million square miles. what percent of land is farmland?

3.) an ibuprofen. suspension for infants contains 100 mg/5.0 no suspension. the recommended dose is 10 mg/kg bnody weight. How many mall of this should be good. yij an infant weighing 181bs (assume 2 sig. figures)

Explanation / Answer

1) Speed = 18 miles/hr
Total distance = 212 Km
Time = (212 km / 1) * (1000 m / 1 km) * (1 mi / 1609.344 m) * (1 hr / 18 mi)
      = 7.32 hr.
  
2) acre = 43560 sq ft
sq mile = 5280² sq ft
954 million * 43560 / (5280 * 5280)
= 1 490 625 sq mi.
= 1.49×10^6 mi^2

percentage, P, of total land is farmland? P = (area of farmland x 100)/(total area)
=(1.491M * 100) / 3.537M = 42.15 %

3)1 Kilogram = 2.20462 Pounds
18 lbs=8.165 kg
10mg/kg=x/8.165kg

do the ratio and proportion

10mg/1kg=x in mg/8.165kg
x=81.65 mg of ibupropfen needed

100mg/5ml=81.65mg/xml
20mg/1ml=81.65mg/xml
x in ml=81.65/20
=4.08 ml or approximately 4.0 ml

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