In Spanish 1 level 8 (Local Tips) it says
mucho; mucha
many, a lot of.
The English alternatives should be “much, a lot of”. Many is muchos; muchas. This has been incorrect for a long time and you would probably have been tipped about it earlier if it wasn’t so much hassle to report.
I’d suggest you re-post your query in the dedicated course forum. Assuming you are talking about the official Memrise course, you’ll find the thread here: