That would be 8, its in the center so forget 9 or 7.
Answer:
26.25 mm
Step-by-step explanation:
On the blueprint of a house, 42 millimeters represents 8 meters. Thus,
42 mm - 8 m,
x mm - 5 m,
mathematically,

Multiples of ten are: 10, 20, 30, 40, 50, 60, & 70.
So there are (7 options that ARE multiplies of ten) out of (75 total options)
Thus, there are (75 - 7 options that are NOT multiples of ten) out of (75 total options).
Answer: 