Lance rides his bike downhill at a pace of 60 miles per hour. when lance is riding uphill, he rides 8 miles per hour slower than on flat roads. if lance’s downhill speed is 4 times faster than his flat-road speed, how fast does he travel uphill? let f represent lance’s pace on flat roads in miles per hour and u represent lance’s pace uphill in miles per hour.

use tape diagrams to solve the problem.

7mph

Step-by-step explanation:

downhill=60mph

f=60mph/4=15mph

u=f-8mph=15mph-8mph=7mph

1gm = 1000mg so 0.1gm = 1000mg

first, convert the weight to kg

160lb * 1kg/2.2lb = 72.7kg

next, the dose

72.7kg * 100mg/kg = 7270mg

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places