Answer:
She baked 640 cookies at first.
Explanation:
Let cookies be x and muffins be y,
Let cookies remaining be z and remaining muffins be a
x = 264 + y
now,
x - 3/8 of x = z
x - 3x/8 = z
or, (8x-3x)/8 = z
so, z = 5x/8
Now,
y - y/2 = a
or, (2y-y)/2 = a
so, a = y/2
Now,
z + a = 588
or, 5x/8 + y/2 = 588
as we know x = 264 + y,
or, 5(264 + y)/8 + y/2 = 588
or, (1320 + 5y)/ 8 + y/2 = 588
or, (2640 + 10y + 8y)/16 = 588
or, 2640 + 18y = 9408
or, 18y = 9408 - 2640
or, 18y = 6768
so, y = 6768/18
so, y = 376
now,
x = 264 + y
or, x = 264 + 376
so, x = 640