Answer:Y=3x(x-4)
Step-by-step explanation:
Hello!
First of all, we can subtract the stretching time. This gives us 20. If we divide by the four laps we get 5 minutes per lap.
Now, one lap is 400 meters (most tracks are), which is equal to 15,748.03 inches. This means it takes her five minutes to walk 15,748.03 inches. This is also equal to 300 seconds, so it takes her 300 minutes per 15,748.03 inches.
But if we round our big inches number to the nearest ten thousandth, we get 16,000, so in a simpler form her pace is 300/16,000. But we need to find in per second. Therefore we will divide by 300 to find how many inches she walks per second. This means she walks about 53.33 inches per second.
I hope this helps!
Answer:
C
Step-by-step explanation:
Calculate AC using Pythagoras' identity in ΔABC
AC² = 20² - 12² = 400 - 144 = 256, hence
AC = 
= 16
Now find AD² from ΔACD and ΔABD
ΔACD → AD² = 16² - (20 - x)² = 256 - 400 + 40x - x²
ΔABD → AD² = 12² - x² = 144 - x²
Equate both equations for AD², hence
256 - 400 + 40x - x² = 144 - x²
-144 + 40x - x² = 144 - x² ( add x² to both sides )
- 144 + 40x = 144 ( add 144 to both sides )
40x = 288 ( divide both sides by 40 )
x = 7.2 → C
Answer:
3
Step-by-step explanation:
A dog buried 18 bones
On Monday he dug up 1/2 of the bones
On Tuesday he dug up 1/3 of the bones
= 1/2 × 18
= 9
= 1/3×18
= 6
Therefore the remaining bones still buried in the ground can be calculated as follows
= 9+6
= 15
= 18-15
= 3
Hence 3 bones are still buried in the ground
