Wusng a calculator, paper and pencil, or mental math.
5. mandy runs 4 km in 18 min. she plans to run in a 15 km race.
how long will it take her to complete the race?

Mandy will take 67.5 mins to complete the 15 km race.

Step-by-step explanation:

Given:

Mandy runs 4 km in 18 min

She plans to run in a 15 km race.

We need to find how much time required to run 15 km.

4 km =18 min

15 km = time required for 15 km race

By Using Unitary method we get,

Time required for 15 km =

Hence time required by Mandy to complete 15 km race is 67.5 mins.

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11