Answer:
Roy is 10 years old at present and Joan is 5 years old at present
Step-by-step explanation:
Let
x----> Roy's age
y----> Joan's age
we know that
x=2y ----> equation A
(x+3)+(y+3)=21 ----> equation B
substitute equation A in equation B
(2y+3)+(y+3)=21
solve for y
3y+6=21
3y=21-6
3y=15
y=5 years
Find the value of x
x=2y ----> x=2(5)=10 years
therefore
Roy is 10 years old at present
Joan is 5 years old at present
Electron—negative charge
Happy studying ^_^
The answer to this question mark will do it all in a few weeks to make it happen again this week at the end
(1) R+G+B=50
(2) R=B+6
(3) G=B-4 so substitute G in (1)
R+B-4+B=50 substitute (2) in here
B+6+B-4+B=50 group like terms and solve
3B+2=50
3B=50-2
B=48/3=16 substitute in (2) and (3)
R=16+6=22
G=16-4=12
Check
22+12+16=50✅
259% increase because 6 x 2 is 12 and 3 is the remainder and 3/6 is 50%