Last year the total number of students in a
school was 5000. This year, the number of
boys increased by 5% and that of girls by
3% and the total number of students
increased by 202. How many boys and girls
were there in the school last year?
Answers
Answer:
last year total number of students in a school was 5000.
b + g = 5000
g = -b + 5000
this year the number of boys increased by 5% and that of girls increased by 3%.
the total number of students increased by 202 to.
.05b + .03g = 202
how many boys and girls were there in a school last year.
Replace g = -b+5000
.05b + .03(-b+5000) = 202
.05b - .03b + 150 = 202
.02b = 202 - 150
.02b = 52
b = 52/.02
b = 2600 boys
and
b = 5000 - 2600
b = 2400 girls
:
:
Check
.05(2600) = 130
.03(2400) = 72
-------------------
total increase: 202
:
Answer:
There were 2600 boys and 2400 girls last year.
Step-by-step explanation:
STEP 1: Define x and y:
Let the number of boys be x
and the number of girls be y
.............................................................................................
STEP 2: Form equations:
x + y = 5000
005x + 0.03y = 202
.............................................................................................
STEP 3: Solve x and y:
x + y = 5000 ---------------------------------- [ 1 ]
0.05x + 0.03y = 202 --------------------- [ 2 ]
.
From [ 1 ]:
x + y = 5000
x = 5000 - y --------------------- Sub into [ 2 ]
.
0.05x + 0.03y = 202
0.05 ( 5000 - y) + 0.03y = 202
250 - 0.05y + 0.03y = 202
0.02y = 48
y = 2400 -------------------- Sub into [ 1 ]
.
x + y = 5000
x + 2400 = 5000
x = 2600
STEP 4: Find the number of boys and girls:
Boys = x = 2600
Girls = y = 2400
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