X/y = 2 so x = 2y
z/x = 4 so z = 4x but x = 2y so z = 4(2y) = 8y
now you have
x = 2y, z = 8y
x + y + z 2y + y + 8y 11y 11
------------ = -----------------------= ------------- = ----------- = 5 1/2
x 2y 2y 2
answer
C. 5 1/2
Let
C=Cynthia's age today
A=Abigail's age today
then
at all times
A=C+8......................(1)
twenty years ago,
A-20=3(C-20)
simplifying
A=3C-40...................(2)
Equate (1) and (2),
C+8=3C-40
8+40=3C-C
C=24
=>
A=32
Check: A-C=8... ok A-20=12 C-20=4 => (A-20)=3(C-20) ...ok
Answer:
Abigail is 32, Cynthia is 24.
Answer:
see explanation
Step-by-step explanation:
(a)
(the side required )² = sum of squares of other 2 sides - ( 2 × product of other 2 sides and cos(angle opposite side required ) )
x² = 12² + 15² - (2 × 12 × 15 × cos71°)
(b)
x² = 144 + 225 - 360cos71°
= 369 - 360cos71° ( take square root of both sides )
x = 
≈ 16 cm ( to the nearest integer )
