A student has some $1 and $5 bills in his wallet. He has a total of 19 bills and that are worth $55. how many of each type of bill does he have

y= 9 ( 5 dollars bill)

x=10 ( one dollar bill)

Step-by-step explanation:

let x be the one dollar bill and y the 5 dollar bill

x+y=19 ⇒ x=19-y

x+5y=55 ( solve by substitute x=19-y)

19-y+5y=55

4y=55-19

4y=36 ⇒ y=36/4

y= 9 ( 5 dollars bill)

x+y=19

x+9=19

x=19-9

x=10 ( one dollar bill)

check :

x+5y=55

10+5(9)=

10+45 = 55 dollars

constant acceleration- a

constant velocity- c

no velocity or acceleration- b

explanation:

for body moving with a constant acceleration, the rate of change of displacement changes over time. this is proven by the increasing gradient of the curve (a) against time.

a body that is moving at constant velocity covers equal distances over equal periods of time, thus the straight line with a constant gradient c.

a stationary body   covers no displacement as time elapses. thus the flat line with   zero gradient.